2019 Paper

Question 1

Which part controls the activities of the cell

Answer 1

Nucleus

Question 2

Which instrument would you use to examine animal cells

Answer 2

Microscope

Question 3

How to calculate density

Answer 3

Mass divided by volume

Question 4

How to know if something has allot of density

Answer 4

Sinks to the bottom the most

Question 5

Put those in order
Air currents cause clouds to move onshore

Water falls to the Earth as precipitation

Heat from the Sun converts liquid water into water vapour

Plants lose water through the process of transpiration

Answer 5

2
3
1
4

Question 6

Describe one way in which water usage in a home could be reduced.

Answer 6

One way in which water usage in a home could be reduced is by fixing leaking taps or pipes Repairing leaks helps to conserve water

Question 7

Describe one difference between a physical change and a chemical change.

Answer 7

One difference between a physical change and a chemical change is that a physical change does not produce a new substance, while a chemical change does
E.g Physical change: Melting ice
Chemical change: Burning wood

Question 8

Is eye color genetically or non gentetically controlled

Answer 8

Genetically

Question 9

Is riding a bike genetically or non gentetically controlled

Answer 9

Non genetically

Question 10

The function of the red blood cells is to

Answer 10

Carry oxygen

Question 11

A student carried out an experiment to investigate the reaction between an acid and a base.
Name a pH indicator the student could have used during this investigation.

Answer 11

Litmus paper

Question 12

What colour is litmus paper when placed in an acid

Answer 12

Red

Question 13

When an acid and a base react, they neutralise each other to produce a neutral solution.
On the pH scale, what number represents a neutral solution?

Answer 13

Seven

Question 14

The student noted a rise in temperature as the acid-base reaction took place.
Is this an example of an endothermic or an exothermic reaction?

Answer 14

Exothermic

Question 15

What are exothermic reactions

Answer 15

Exothermic reactions are chemical reactions. which release energy from the chemicals into the surroundings

Question 16

What are endothermic reactions

Answer 16

Endothermic reactions are chemical reactions in which the reactants absorb heat energy from the surroundings to form products

Question 17

Name an instrument that could be used to measure the time taken for the journey of a cyclist

Answer 17

Stopwatch

Question 18

How to calculate speed

Answer 18

Speed=distance divided by time

Question 19

Name a human activity which has led to global warming.

Answer 19

One human activity which has led to global warming is the burning of fossil fuels, such as coal, oil, and gas.

This releases carbon dioxide (CO₂) and other greenhouse gases into the atmosphere, which trap heat and cause the Earth’s temperature to rise. 🌍🔥

Question 20

State a consequence of rising sea levels on coastal areas.

Answer 20

One consequence of rising sea levels on coastal areas is increased flooding.

This can damage homes, roads, and infrastructure, and may even force people to move away from their homes in low-lying areas

Question 21

Ice sheets are the natural habitat of animals such as polar bears. State one adaptation of polar bears that makes them suited to this habitat.

Answer 21

One adaptation of polar bears that makes them suited to ice sheet habitats is their thick layer of blubber and dense fur, which helps to keep them warm in freezing temperatures

Question 22

Would you expect the population of polar bears to increase or decrease as ice sheets

Answer 22

Decrease

Question 23

What name is given to the change of state when liquid water becomes solid ice

Answer 23

Freezing

Question 24

Describe what happens in the respiratory system when a person breathes in.

Answer 24

When a person breathes in (inhales), air enters the body through the nose or mouth, then travels down the trachea (windpipe), passes into the bronchi, and finally reaches the lungs.

In the lungs, the air moves into tiny air sacs called alveoli, where oxygen passes into the blood. At the same time, carbon dioxide moves from the blood into the alveoli to be breathed out later.

Also, the diaphragm contracts and moves down, creating more space in the chest and helping to pull air into the lungs

Question 25

A star and all of the objects that orbit it is called a

Answer 25

Solar system

Question 26

A system of billions of stars is called a

Answer 26

Galaxy

Question 27

What is meant by the boiling point of a substance?

Answer 27

The boiling point of a substance is the temperature at which it changes from a liquid to a gas. At this temperature, the liquid boils, and bubbles of gas form throughout the liquid and rise to the surface. 🌡️💧➡️💨

Question 28

student was asked to investigate what effect adding salt has on the boiling point of water. Write a suitable hypothesis for this investigation.

Answer 28

If salt is added to water, then the boiling point of the water will increase." This means you expect the water to boil at a higher temperature when salt is added. 🧂💧🌡️

Question 29

The laboratory instrument used to measure the mass of the salt is

Answer 29

Electric balance

Question 30

Why may a student repeat an investigation five times

Answer 30

increase the accuracy and reliability of the results student to calculate an average, giving a more trustworthy and fair outcome. ✅📊

Question 31

Name meter X, which was used to determine the resistance of the LDR.

Answer 31

Ohmmeter

Question 32

Name a piece of equipment the student could have used to accurately measure 20 cm of water.

Answer 32

Graduated cylinder

Question 33

A smart watch uses a green LED to measure a person's pulse by shining green light into the red blood in the person's wrist. Describe one other technological application of physics that is used in everyday life.

Answer 33

GPS devices rely on satellite signals and the physics of radio waves to calculate a person's location on Earth

Question 34

Explain why some of the tubes connected to the heart are coloured red and some of them are coloured blue.

Answer 34

to show the difference in the type of blood they carry: Red vessels (arteries) carry oxygen-rich blood from the heart to the rest of the body.❤️ Blue vessels (veins) carry oxygen-poor blood back to the heart from the body💙

Question 35

How to calculate voltage

Answer 35

voltage = current x resistance

Question 36

What do you understand by the term sustainability?

Answer 36

Sustainability refers to the ability to meet the needs of the present without compromising the ability of future generations to meet their own needs It’s the use of a resource so that it does not run out

Question 37

Suggest one way in which we can reduce how much electrical energy we use.

Answer 37

One way to reduce electrical energy usage is by unplugging devices when they are not in use.

Question 38

Identify two renewable sources of energy

Answer 38

Solar Wind

Question 39

Do you agree or disagree with the use of animals in scientific research?

Answer 39

disagree because animals can feel pain and distress, and some believe it's unethical to harm animals for human benefit

Question 40

Human health is affected by environmental factors such as stress. Name another environmental factor which has an effect on human health.

Answer 40

Pollution

Question 41

State another example of how bacteria could have an effect on human health.

Answer 41

Bacteria can cause disease such as TB or tooth decay

Question 42

Describe one difference between sexual and asexual reproduction.

Answer 42

Asexual reproduction involves one parent and produces offspring that are genetically identical to each other and to the parent. S exual reproduction involves two parents and produces offspring that are genetically unique

Question 43

Outline the theory of evolution by natural selection.

Answer 43

suggests that species evolve over time through the following key principles Variation: Within a population, individuals show variation in traits (e.g., size, color, speed). These variations are often inherited. Competition: Organisms produce more offspring than can survive, leading to competition for resources such as food, shelter, and mates. Survival of the Fittest: Individuals with traits that are better suited to their environment are more likely to survive and reproduce. These advantageous traits are passed on to the next generation. Inheritance: Over time, beneficial traits become more common in the population, while less beneficial traits may disappear. Speciation: As these changes accumulate, populations can become so different that they form new species.

Question 44

identify a gas which is a component of the Earth's atmosphere and which is in plentiful supply.

Answer 44

Oxygen Nitrogen

Question 45

Why should the use of the gas helium (He) in birthday balloons be avoided?

Answer 45

Because the availability of helium is seriously threatened

Question 46

How to know if somethings is a solid at room temperature

Answer 46

Particles are packed closely together

Question 47

On January 2a 2019, the Chinese Chang'e-4 lander touched down on the far side or 'dark side' of the Moon. Explain why this side of the Moon is never visible from Earth.

Answer 47

the Moon is in synchronous rotation with Earth, meaning it takes the same amount of time to rotate once on its axis as it does to orbit Earth

Question 48

What is an asteroid?

Answer 48

An asteroid is a small rocky object that orbits the Sun, mostly found in the Asteroid Belt between Mars and Jupiter. They are made up of rock, metal, and other elements, and are much smaller than planets

Question 49

The hammer and feather were dropped at the same time from the same height and hit the surface of the Moon at the same time. A hammer falls much faster on Earth than it does on the Moon. Explain why.

Answer 49

experiment conducted by astronaut David Scott in 1971, they hit the surface at the same time because there is no air resistance on the Moon to slow the feather down. On Earth, air resistance causes the feather to fall more slowly than the hammer, but on the Moon, the absence of atmosphere means both objects fall at the same rate regardless of their mass. 🌑🔨🪶