Biology 6

Question 1

Yellow fever is a viral disease caused by the yellow fever virus, which belongs to the Flaviviridae family. Here are some key biology points about yellow fever:

Answer 1

Transmission: Yellow fever is primarily transmitted to humans through the bite of infected Aedes mosquitoes, particularly Aedes aegypti. These mosquitoes typically breed in stagnant water and are commonly found in urban areas.
Virus: The yellow fever virus is a single-stranded RNA virus. It is an arthropod-borne virus (arbovirus) and is closely related to other flaviviruses such as dengue virus, Zika virus, and West Nile virus.
Symptoms: The symptoms of yellow fever typically include fever, headache, muscle pain, nausea, vomiting, and jaundice (yellowing of the skin and eyes). In severe cases, yellow fever can lead to liver failure, hemorrhage, and death.
Reservoir: In tropical regions of Africa and South America, non-human primates (such as monkeys) serve as the primary reservoirs for the yellow fever virus. Mosquitoes become infected with the virus when they bite infected primates.
Vaccination: Vaccination is the most effective way to prevent yellow fever. The yellow fever vaccine is a live attenuated vaccine that provides long-lasting immunity against the virus. It is recommended for individuals living in or traveling to areas where yellow fever is endemic.
Diagnosis: Yellow fever can be diagnosed based on symptoms, travel history to endemic areas, and laboratory tests such as serological assays and polymerase chain reaction (PCR) testing for the virus.
Treatment: There is no specific antiviral treatment for yellow fever. Supportive care, including rest, hydration, and treatment of symptoms, is the mainstay of management for patients with yellow fever. In severe cases, hospitalization and intensive care may be necessary.
Prevention: In addition to vaccination, other preventive measures for yellow fever include avoiding mosquito bites by using insect repellents, wearing protective clothing, and sleeping under mosquito nets, especially during peak mosquito activity times

Question 2

Yellow fever Transmission

Answer 2

Transmission: Yellow fever is primarily transmitted to humans through the bite of infected Aedes mosquitoes, particularly Aedes aegypti. These mosquitoes typically breed in stagnant water and are commonly found in urban areas.

Question 3

Yellow fever virus

Answer 3

Virus: The yellow fever virus is a single-stranded RNA virus. It is an arthropod-borne virus (arbovirus) and is closely related to other flaviviruses such as dengue virus, Zika virus, and West Nile virus.

Question 4

Yellow fever symptoms

Answer 4

Symptoms: The symptoms of yellow fever typically include fever, headache, muscle pain, nausea, vomiting, and jaundice (yellowing of the skin and eyes). In severe cases, yellow fever can lead to liver failure, hemorrhage, and death.

Question 5

Yellow fever vaccination

Answer 5

Vaccination: Vaccination is the most effective way to prevent yellow fever. The yellow fever vaccine is a live attenuated vaccine that provides long-lasting immunity against the virus. It is recommended for individuals living in or traveling to areas where yellow fever is endemic.

Question 6

Convergent Evolution:

Answer 6

Convergent evolution occurs when unrelated species independently evolve similar traits or characteristics due to similar environmental pressures or ecological niches. Despite not being closely related, these species develop analogous traits to adapt to similar environmental challenges. An example of convergent evolution is the development of wings in birds, bats, and insects, which allow them to fly despite their different evolutionary origins.

Question 7

Divergent Evolution:

Answer 7

Divergent evolution occurs when two or more closely related species evolve different traits or characteristics over time, often due to adapting to different environmental conditions or ecological niches. As a result, these species become increasingly distinct from each other. An example of divergent evolution is the finches on the Galápagos Islands, which evolved different beak shapes and sizes to exploit different food sources on different islands.

Question 8

Adaptive Radiation:

Answer 8

Adaptive radiation is a type of divergent evolution in which a single ancestral species rapidly diversifies into a wide variety of descendant species, each adapted to different ecological niches. This diversification often occurs when organisms colonize new environments with diverse ecological opportunities and face reduced competition. An example of adaptive radiation is the finches in the Galápagos Islands, which diversified into multiple species with different beak shapes and feeding habits.

Question 9

Parallel Evolution:

Answer 9

Parallel evolution occurs when two related species independently evolve similar traits or characteristics due to similar selection pressures, even though they may have different evolutionary origins. Unlike convergent evolution, which involves unrelated species, parallel evolution involves closely related species that evolve similar traits independently. An example of parallel evolution is the evolution of streamlined body shapes in dolphins and ichthyosaurs, both of which are adapted for efficient swimming in aquatic environments despite their different evolutionary histories.

Question 10

Parenchyma

Answer 10

Parenchyma cells are found throughout the plant and serve various functions, including storage, photosynthesis, and secretion. In young plants, parenchyma cells provide structural support and help maintain the overall integrity of the plant tissues.

Question 11

Collenchyma

Answer 11

Collenchyma cells are elongated cells with thickened cell walls, primarily found in the cortex of stems and leaves. They provide flexible support to young plant organs, allowing them to bend without breaking. Collenchyma tissues are especially abundant in the growing regions of young plants.

Question 12

Sclerenchyma

Answer 12

: Sclerenchyma cells are specialized for providing mechanical support and protection. They have thick, lignified cell walls that provide rigidity and strength to plant tissues. Sclerenchyma tissues are often found in the vascular bundles, seed coats, and woody parts of plants, providing support to young stems and roots as they elongate and mature.

Question 13

Part of the brain that controls heartbeat respiration and peristalsis

Answer 13

Medulla oblongata

Question 14

Which supporting tissue is essential for young plant

Answer 14

Collenchyma

Question 15

Do animal cells have cell wall

Answer 15

No, animal cells do not have cell walls. Unlike plant cells, which have a rigid cell wall made of cellulose, animal cells are surrounded by a flexible plasma membrane or cell membrane. The plasma membrane serves as a protective barrier around the cell, controlling the movement of substances in and out of the cell and providing structure to the cell.

Question 16

Do animal cells have cell wall

Answer 16

No, animal cells do not have cell walls. Unlike plant cells, which have a rigid cell wall made of cellulose, animal cells are surrounded by a flexible plasma membrane or cell membrane. The plasma membrane serves as a protective barrier around the cell, controlling the movement of substances in and out of the cell and providing structure to the cell.

Question 17

Do animal cells have chloroplast

Answer 17

No, animal cells do not have chloroplasts. Chloroplasts are specialized organelles found in plant cells and some protists, such as algae. They are responsible for photosynthesis, the process by which plants use sunlight to convert carbon dioxide and water into glucose and oxygen. Animal cells do not perform photosynthesis, so they do not contain chloroplasts. Instead, animal cells obtain energy by consuming organic molecules through processes such as cellular respiration.

Question 18

Variation

Answer 18

Variation refers to differences among individuals of the same species. In the context of plant breeding, variation allows plant breeders to select for desirable traits, such as disease resistance, among different individuals. By identifying plants with natural resistance to certain diseases and selectively breeding them, plant breeders can develop new varieties that are more resistant to diseases, ultimately leading to disease-resistant plant varieties.

Question 19

Heredity

Answer 19

Heredity refers to the passing of traits or characteristics from parents to offspring through genetic transmission. It involves the transmission of genetic information encoded in the DNA molecules from one generation to the next. These genetic traits can include physical characteristics, such as eye color or height, as well as physiological traits and predispositions to certain diseases. Heredity plays a crucial role in determining the genetic makeup and traits of individuals within a species.

Question 20

Heredity and variations in creating disease resistant plant species

Answer 20

The answer “variation” is more appropriate for the context of producing disease-resistant plant varieties because variation refers to the differences or diversity in traits within a population.

In the context of plant breeding for disease resistance, variation is essential because it provides a pool of genetic diversity from which breeders can select plants with desirable traits, such as resistance to specific diseases. By selecting plants with natural genetic variation that confers disease resistance, breeders can develop new plant varieties that are better able to withstand disease pressure.

While heredity (the passing of traits from parents to offspring) is also important in the process, variation is specifically highlighted in this context because it emphasizes the need for genetic diversity to produce disease-resistant plant varieties.

Question 21

Continuous variation

Answer 21

Continuous variation refers to variation in a characteristic that can take any value within a range. This type of variation is often influenced by multiple genes and environmental factors. Examples include height, weight, and blood pressure in humans.

Question 22

Physiological variation

Answer 22

refers to variations in physiological functions or processes within an organism. These variations can occur due to factors such as age, gender, health status, or environmental conditions. Examples include variations in heart rate, metabolism, or hormone levels.

Question 23

Discontinuous variation

Answer 23

Discontinuous variation refers to variation in a characteristic that falls into distinct categories or groups with no intermediate forms. This type of variation is often controlled by a single gene or a small number of genes with distinct alleles. Examples include blood type in humans (A, B, AB, O) and coat color in animals (black, brown, white).

Question 24

Largest game reserve in Nigeria

Answer 24

Yankari game reserve

Question 25

The association between sharks and remora fish is a classic example of

Answer 25

The association between sharks and remora fish is a classic example of mutualism, a type of symbiotic relationship where both species benefit. Remora fish have a specialized dorsal fin that acts as a suction cup, allowing them to attach themselves to larger marine animals like sharks, whales, or turtles. By hitching a ride on the shark, remoras gain access to transportation, protection, and access to food scraps left behind by the shark’s feeding activities. In return, remoras clean parasites and debris from the shark’s skin, providing a valuable cleaning service that benefits the shark’s health and hygiene. Thus, both species benefit from this association, making it a mutualistic relationship.

Question 26

Intelligence reason and memory is controlled by

Answer 26

Cerebrum

Question 27

cambium

Answer 27

The cambium is a layer of meristematic tissue in plants, specifically in the vascular tissue of stems and roots. It is responsible for secondary growth, which involves the production of secondary xylem (wood) and secondary phloem. The cambium divides to produce new cells, which then differentiate into the xylem cells that transport water and minerals and the phloem cells that transport sugars and other organic compounds. This process contributes to the increase in girth or diameter of woody plants over time.

Question 28

The layer between the epidermis and pericycle in a plant is called the

Answer 28

The layer between the epidermis and pericycle in a plant is called the cortex

Question 29

Treponema pallidum

Answer 29

Treponema pallidum is a species of spiral-shaped bacteria that causes syphilis, a sexually transmitted infection (STI). Syphilis can have various stages and symptoms, including genital sores, skin rashes, and, if left untreated, serious complications affecting the heart, brain, and other organs. Treponema pallidum is highly contagious and is typically transmitted through sexual contact. Treatment usually involves antibiotics such as penicillin.

Question 30

Bacillus anthracis

Answer 30

Bacillus anthracis is a bacterium that causes anthrax, a serious infectious disease that primarily affects animals but can also occasionally infect humans. Anthrax can manifest in several forms, including cutaneous (skin), inhalational (respiratory), and gastrointestinal (digestive) anthrax.

Bacillus anthracis produces spores that can survive in the environment for long periods, making it a potential biological weapon. Infection typically occurs through contact with contaminated animals or their products, inhalation of spores, or ingestion of contaminated food.

Symptoms of anthrax vary depending on the type of exposure but can include fever, chills, cough, difficulty breathing, nausea, vomiting, and skin lesions. Inhalational anthrax is the most severe form and can be fatal if not promptly treated with antibiotics.

Preventive measures include vaccination for at-risk individuals, proper handling of potentially contaminated materials, and surveillance of livestock.

Question 31

Neisseria gonorrhoeae

Answer 31

Neisseria gonorrhoeae is a bacterium responsible for the sexually transmitted infection gonorrhea. It primarily infects the mucous membranes of the urethra, cervix, rectum, throat, and eyes. Gonorrhea is transmitted through sexual contact with an infected individual.

Symptoms of gonorrhea can vary depending on the site of infection but commonly include painful urination, discharge from the genitals, and pelvic pain. However, many infected individuals may not experience any symptoms, especially in the early stages of infection.

If left untreated, gonorrhea can lead to serious complications such as pelvic inflammatory disease (in women), infertility, and an increased risk of contracting or transmitting other sexually transmitted infections, including HIV.

Treatment typically involves antibiotics, although antibiotic resistance in Neisseria gonorrhoeae has become a growing concern in recent years. Prevention methods include practicing safe sex, using condoms consistently and correctly, and getting regular screenings for sexually transmitted infections.

Question 32

Vibrio cholerae

Answer 32

Vibrio cholerae is a bacterium responsible for causing cholera, a severe diarrheal disease. Cholera is typically transmitted through the ingestion of contaminated water or food, particularly in areas with poor sanitation and hygiene practices.

Symptoms of cholera include profuse watery diarrhea, vomiting, and dehydration. In severe cases, cholera can lead to rapid loss of body fluids and electrolytes, which can result in shock, kidney failure, and death if left untreated.

Treatment for cholera involves prompt rehydration with oral rehydration salts or intravenous fluids to replace lost fluids and electrolytes. Antibiotics may also be prescribed to reduce the duration and severity of symptoms, although they do not replace the need for rehydration therapy.

Preventive measures for cholera include ensuring access to safe drinking water, practicing good hygiene, especially handwashing with soap and clean water, and proper sanitation practices, such as safely disposing of human waste and avoiding eating raw or undercooked seafood, particularly shellfish harvested from contaminated waters. Vaccines are also available for individuals at high risk of cholera infection, such as travelers visiting endemic areas or those living in regions prone to cholera outbreaks.

Question 33

Spiders and prawns belong to different taxonomic groups and have distinct biological characteristics

Answer 33

Body Structure:
Spiders belong to the class Arachnida and have two body segments: the cephalothorax and the abdomen. They have eight legs and lack antennae.
Prawns belong to the class Malacostraca under the phylum Arthropoda. They have a body divided into two main regions: the cephalothorax and the abdomen. Prawns have ten legs, including five pairs of walking legs, and possess long antennae.

Question 34

The cortex has 3 parts

Answer 34

Hypodermis general cortex and endodermis

Question 35

Spiders and prawns

Answer 35

Spiders reproduce sexually, with males transferring sperm to females through specialized structures called pedipalps.
Prawns also reproduce sexually, with fertilization occurring externally. Female prawns release eggs into the water, where they are fertilized by sperm from males.

Question 36

Clay soil

Answer 36

Particle Size: Contains very fine particles, smaller than 0.002 mm in diameter.
Texture: Smooth and sticky when wet, hard and compact when dry.
Water Retention: High water retention capacity, leading to poor drainage and slow water infiltration.
Nutrient Content: Rich in nutrients and minerals due to high surface area, but nutrients may be tightly bound and less accessible to plants.
Workability: Difficult to work with when wet, prone to compaction, but can be improved with organic matter.

Question 37

Loan soil

Answer 37

Particle Size: Balanced mixture of sand, silt, and clay particles.
Texture: Soft, crumbly, and well-structured.
Water Retention: Moderate water retention capacity, providing good drainage and adequate moisture for plant growth.
Nutrient Content: Nutrient-rich with good fertility, providing essential nutrients for plant growth.
Workability: Easy to work with, suitable for gardening and farming activities.

Question 38

Sandy soil

Answer 38

Particle Size: Contains large sand particles, ranging from 0.05 to 2.0 mm in diameter.
Texture: Gritty and loose, does not hold together well.
Water Retention: Low water retention capacity, fast drainage, and rapid infiltration.
Nutrient Content: Low in nutrients and organic matter, leaches nutrients quickly due to fast drainage.
Workability: Easy to work with, but requires frequent irrigation and fertilization to support plant growth.

Question 39

Laterite soil

Answer 39

Formation: Formed by weathering of parent rock material, typically rich in iron and aluminum oxides.
Texture: Hard and compacted when dry, but soft and easily eroded when wet.
Water Retention: Variable water retention capacity, depending on the degree of weathering and drainage characteristics.
Nutrient Content: Low in nutrients and organic matter, often acidic due to leaching of minerals.
Agricultural Use: Requires appropriate management practices, such as soil amendment and erosion control, for sustainable agriculture.

Question 40

Pollen grain

Answer 40

A pollen grain is a microscopic structure produced by the male reproductive organs (anthers) of seed plants. It contains the male gametes (sperm cells) needed for fertilization.

Question 41

Anther

Answer 41

An anther is the part of the flower where pollen grains are produced. It is typically located at the tip of the filament.

Question 42

Stigma

Answer 42

The stigma is the receptive surface of the female reproductive organ (pistil) of a flower. It is where pollen grains land and germinate during pollination.

Question 43

Filament

Answer 43

The filament is the stalk-like structure that supports the anther in a flower. It connects the anther to the rest of the flower’s reproductive organs.

Question 44

The pons is a structure located in the brainstem, specifically between the midbrain (mesencephalon) and the medulla oblongata. It is a part of the hindbrain. The pons serves several important functions:

Answer 44

Relay Center: It acts as a relay station, transmitting signals between different parts of the brain, including the cerebellum and cerebral cortex.
Respiratory Control: The pons plays a crucial role in regulating breathing by controlling the rate and depth of respiration. It contains respiratory centers that receive input from chemoreceptors and adjust breathing accordingly.
Sleep Regulation: The pons is involved in the regulation of sleep and arousal. It interacts with other brain regions to coordinate transitions between different sleep stages, including REM (rapid eye movement) sleep and non-REM sleep.
Motor Control: Although the primary motor functions are largely regulated by the cerebral cortex and the cerebellum, the pons also contributes to motor control, especially in coordinating movements of the face and eyes.
Sensory Pathways: The pons contains pathways that transmit sensory information from the body to the brain and vice versa. It serves as a conduit for signals related to touch, proprioception (awareness of body position), and other sensory modalities.

Question 45

micro decomposer

Answer 45

micro decomposer,” which refers to microorganisms such as bacteria and fungi that break down organic matter into simpler substances. These microorganisms play a crucial role in the decomposition process, breaking down dead plants and animals into nutrients that can be recycled back into the ecosystem. Therefore, the correct answer to your question would likely be option D, bacteria, as they are one of the key micro decomposers in most ecosystems.

Question 46

Pulmonary circulation:

Answer 46

This refers to the movement of blood between the heart and the lungs. It carries deoxygenated blood from the heart to the lungs, where it picks up oxygen and releases carbon dioxide.

Question 47

Systemic circulation:

Answer 47

This is the movement of blood between the heart and the rest of the body, excluding the lungs. It carries oxygenated blood from the heart to the body tissues and returns deoxygenated blood back to the heart.

Question 48

Single circulation:

Answer 48

This is a type of circulatory system found in some lower vertebrates, where blood flows through the heart once in each complete circuit of the body. It includes organisms like fish.

Question 49

Double circulation:

Answer 49

This is a more efficient circulatory system found in mammals, birds, and some reptiles, where blood passes through the heart twice in each complete circuit of the body. It includes both pulmonary circulation (to the lungs) and systemic circulation (to the body).

Question 50

The complete metamorphosis, which is characteristic of insects such as butterflies, beetles, and flies, consists of four stages:

Answer 50

Egg: The life cycle begins with the egg stage, where the female insect lays eggs, often on or near a suitable food source for the larvae.
Larva (Caterpillar, grub, maggot, etc.): After hatching from the egg, the larva emerges. Larvae are typically specialized for feeding and growth. They undergo multiple molts, shedding their exoskeletons as they grow.
Pupa (Chrysalis, cocoon, etc.): Once the larva has completed its growth, it enters the pupal stage. During this stage, the insect undergoes a dramatic transformation inside a protective casing. Inside the pupa, the larval tissues are broken down and reorganized into the adult form.
Adult: After the transformation is complete, the adult insect emerges from the pupal casing. The adult stage is the reproductive stage of the insect’s life cycle, and it typically involves finding a mate and laying eggs to begin the cycle anew.

Question 51

Nymph cockroaches

Answer 51

In cockroaches, as in other insects that undergo incomplete metamorphosis, the immature form is called a nymph. Cockroach nymphs resemble miniature versions of adults but lack fully developed wings and reproductive organs. As nymphs grow, they molt several times, shedding their exoskeletons to accommodate their increasing size. After several molts, they reach adulthood. Unlike insects that undergo complete metamorphosis, such as butterflies, cockroaches and other insects with incomplete metamorphosis do not have a pupal stage in their life cycle.

Question 52

Epigeal germination refers to the type of seed germination where the cotyledons emerge above the soil surface. Some characteristics of epigeal germination include:

Answer 52

Hypocotyl elongation: The portion of the embryonic axis between the radicle and the cotyledons elongates, pushing the cotyledons above the soil surface.
Cotyledon emergence: The cotyledons, which are the seed leaves containing stored nutrients, emerge above the soil surface and become green as they begin photosynthesis.
Plumule development: The plumule, which is the embryonic shoot tip, emerges from between the cotyledons and develops into the shoot system of the seedling.
Limited nutrient dependence: Epigeal seedlings initially rely on the nutrients stored in the cotyledons for energy until they can establish photosynthesis and obtain nutrients from the soil through their roots.
Vulnerability to environmental factors: Since the cotyledons are exposed above the soil surface, epigeal seedlings may be more vulnerable to environmental factors such as herbivory, desiccation, and extreme temperatures compared to hypogeal seedlings whose cotyledons remain below ground.

Question 53

Hypogeal germination refers to the type of seed germination where the cotyledons remain below the soil surface. Here are some characteristics of hypogeal germination:

Answer 53

Cotyledon retention: In hypogeal germination, the cotyledons remain underground and do not emerge above the soil surface.
Radicle emergence: The radicle, which is the embryonic root, elongates and emerges from the seed, anchoring the seedling in the soil and absorbing water and nutrients.
Plumule development: The plumule, which is the embryonic shoot tip, remains within the seed and does not emerge above the soil surface during early growth stages.
Limited photosynthesis: Since the cotyledons remain underground and are not exposed to light, they do not undergo photosynthesis during early growth stages. Instead, they primarily serve as nutrient storage organs, providing energy for the developing seedling.
Reduced vulnerability: Hypogeal seedlings are often less vulnerable to environmental factors such as herbivory, desiccation, and extreme temperatures compared to epigeal seedlings, as their cotyledons are protected underground.
Overall, hypogeal germination is characterized by the retention of cotyledons underground and the emergence of the radicle to initiate seedling growth.

Question 54

Estuarine habitat

Answer 54

Fluctuations in salinity
More diversity than fresh water

Question 55

Here are some characteristics of lichens:

Answer 55

Symbiotic Relationship: Lichens are formed by the mutualistic association between a fungus (usually an ascomycete) and either green algae or cyanobacteria.
Growth Forms: Lichens exhibit various growth forms, including crustose (crust-like), foliose (leaf-like), and fruticose (shrub-like).
Environmental Indicators: Lichens are sensitive to environmental factors such as air quality, pollution, and climate change, making them useful bioindicators.
Tolerance to Extreme Conditions: Lichens can colonize diverse habitats, ranging from arctic tundra to deserts, and are often found on rocks, soil, trees, and other substrates.
Photosynthesis: The algae or cyanobacteria component of lichens perform photosynthesis, providing nutrients to the fungal partner.
Reproduction: Lichens reproduce through the dispersal of fungal spores or specialized reproductive structures called soredia or isidia.
Slow Growth: Lichens grow very slowly, with some species taking decades or even centuries to reach maturity.
Survival Strategies: Lichens have developed various adaptations to survive harsh environmental conditions, including desiccation tolerance and the ability to withstand extreme temperatures.
Ecological Importance: Lichens play crucial roles in ecosystems by contributing to soil formation, nitrogen fixation, and providing food and habitat for various organisms.
Economic Uses: Lichens have been used traditionally for dye production, medicine, food, and as indicators of forage quality for livestock.

Question 56

Countershading

Answer 56

Characteristics: Countershading is a form of camouflage where an animal’s body is colored darker on the upper side and lighter on the underside. This helps to counteract the effects of overhead lighting and makes the animal less visible to predators and prey.
Key Points: It creates an illusion of flatness, making it difficult for predators to detect the animal’s shape.
Example: The blue whale has countershading, with a dark blue dorsal side and a lighter ventral side, which helps it blend into the ocean when viewed from above or below.

Question 57

Disruptive Coloration:

Answer 57

Characteristics: Disruptive coloration involves patterns or markings that break up an animal’s outline, making it difficult for predators or prey to distinguish its shape.
Key Points: It confuses the visual system of predators or prey, making it harder for them to target the animal.
Example: The jaguar has rosette-like markings on its fur, which help it blend into the dappled light and shadows of its forest habitat, making it less visible to potential prey.

Question 58

Cryptic Coloration:

Answer 58

Characteristics: Cryptic coloration, also known as camouflage, involves color patterns that allow an animal to blend in with its environment, making it nearly invisible to predators or prey.
Key Points: It helps the animal avoid detection by matching its background or mimicking objects in its surroundings.
Example: The peppered moth has light-colored speckled wings that resemble lichen-covered tree bark, providing camouflage against tree trunks and branches.

Question 59

Dangerous Coloration (Aposematism):

Answer 59

Characteristics: Dangerous coloration involves bright colors or bold patterns that advertise an animal’s toxicity, venom, or unpalatability to potential predators.
Key Points: It serves as a warning signal to predators, indicating that the animal is dangerous or distasteful.
Example: The poison dart frog has vibrant colors, such as bright red, yellow, or blue, which signal its toxicity to predators and deter them from attacking.

Question 60

The mandibulate soldiers in termite colonies have several important functions:

Answer 60

Defense: Mandibulate soldiers use their powerful mandibles to defend the colony against predators, such as ants or other termites, by biting and cutting them.
Colony protection: They guard the entrances to the nest and tunnels, preventing intruders from entering and potentially harming the colony.
Alarm signal: Mandibulate soldiers can release alarm pheromones when they detect a threat, alerting other members of the colony to the presence of danger.
Nest maintenance: Soldiers may assist in repairing or sealing breaches in the nest structure, helping to maintain the integrity of the colony’s environment.

Question 61

A device commonly used to measure the speed of wind is an

Answer 61

A device commonly used to measure the speed of wind is an anemometer. An anemometer typically consists of cups or blades that rotate in response to the wind’s force. The rotation speed is then measured electronically or mechanically to determine the wind speed. Some modern anemometers also incorporate additional features such as wind direction sensors.

Question 62

Eutrophication

Answer 62

Eutrophication is a process in which a body of water becomes overly enriched with nutrients, typically nitrogen and phosphorus. This enrichment often occurs due to runoff from agricultural areas, urban areas, and sewage treatment plants. As a result of this excess nutrient input, algae and other aquatic plants grow rapidly, leading to an overgrowth known as an algal bloom. When these plants die and decompose, the process consumes oxygen, leading to a depletion of oxygen levels in the water, which can harm aquatic life. Eutrophication can result in decreased water quality, loss of biodiversity, and disruptions to ecosystems.

Question 63

Aetiolation

Answer 63

Aetiolation is a phenomenon observed in plants when they grow abnormally due to insufficient light. It results in elongated, pale stems and small, poorly developed leaves. Aetiolation occurs because plants produce less chlorophyll in low light conditions, leading to reduced photosynthesis and weakened growth. This response is an adaptation to help plants reach for more light, but it can result in weakened structures and reduced overall health.

Question 64

Cork

Answer 64

: Cork is a protective tissue that develops from the cork cambium, also known as the phellogen. It is formed outside the cork cambium and serves as the outermost layer of the stem. Cork cells are dead at maturity and contain suberin, a waxy substance that makes them impermeable to gases and water. Cork provides protection against physical damage, pathogens, and water loss.

Question 65

Cambium:

Answer 65

Cambium is a layer of actively dividing cells found in the vascular tissue of plants, primarily in the stems and roots. It is responsible for secondary growth, which leads to an increase in the diameter of the stem or root. The two main types of cambium are vascular cambium and cork cambium. Vascular cambium produces secondary xylem (wood) to the inside and secondary phloem to the outside, contributing to the growth of the plant. Cork cambium produces cork cells externally, adding to the protective outer layer of the stem.

Question 66

The endoplasmic reticulum (ER)

Answer 66

The endoplasmic reticulum (ER) is the organelle that provides a surface for the attachment of proteins. Specifically, proteins are synthesized and modified on the rough endoplasmic reticulum (RER), which is studded with ribosomes on its surface. These ribosomes are responsible for protein synthesis. After synthesis, proteins may undergo further modification and processing within the lumen of the ER before being transported to their final destination within the cell or outside of the cell.

Question 67

The Golgi apparatus

Answer 67

The Golgi apparatus, or Golgi body, is another organelle involved in the modification and processing of proteins. It receives proteins synthesized in the endoplasmic reticulum and further modifies them by adding sugars, lipids, or other molecules to them. The Golgi apparatus also sorts and packages these modified proteins into vesicles for transport to their final destinations, either within the cell or outside of the cell. Additionally, it plays a role in the synthesis of certain carbohydrates and the formation of lysosomes.

Question 68

Trichocysts in Paramecium

Answer 68

Trichocysts in Paramecium are specialized organelles involved in defense mechanisms. When Paramecium detects a threat, such as a predator or an unfavorable environmental condition, trichocysts rapidly discharge long, thin threads called trichocyst filaments. These filaments act as a deterrent to predators by entangling or immobilizing them, helping the Paramecium escape from harm. Trichocysts essentially serve as a means of protection and defense for the Paramecium against potential dangers in its environment.

Question 69

Physiological variation:

Answer 69

Physiological variation: This type of variation involves differences in the physiological functions or processes of organisms within a population. These variations can include differences in metabolism, hormone levels, enzyme activity, or other internal processes that affect an organism’s function. Physiological variations can be influenced by factors such as age, sex, diet, and environmental conditions. Examples include variations in heart rate, blood pressure, or levels of certain hormones.