Environmental Sustainability

Question 1

Explain greenhouse effect

Answer 1

• Human activities causes an increase in greenhouse gases (methane, CFC, Co2)
• when sunlight enters the atmosphere, some is reflected back into space in the form of infrared rays
• more greenhouse gases present in the atm will absorb more heat energy
• more heat is trapped and temperature of the earth increases

Question 2

State one benefit and 1 side effect of greenhouse gases.

Answer 2

• -Benefit–
• maintain optimal atmospheric temperature
• -Side effect–
• global warming
• extinction of flora and fauna
• climate change
• thinning of ozone layer

Question 3

In an experiment to determine the BOD level of a water source, a quick decolourisation of methylene blue solution indicates ___?

Answer 3

indicates high BOD level

Question 4

What causes eutrophication?

Answer 4

• excessive usage of nitrate and phosphate fertilisers

- causes algae bloom

Question 5

In a water source where eutophicration occurs, BOD level is ___?

Answer 5

high

Question 6

How does acid rain occurs?

Answer 6

• burning of fossil fuels, factories and vehicles release CO, S02, NO2
• CO, SO2, NO2 combine with water vapour to form sulhuric acid and niric acid
• come down as acid rain

Question 7

What are the effects of acid rain

Answer 7

• corrodes buildings wall and paints
• reduces number of plankton population –> disrupts food chain
• destroys leaf and root tissues
• contaminate drinking water
• skin diseases and tissue damage

Question 8

State 2 methods to reduce release of pollutants

Answer 8

• catalytic converters

- scrubbers

Question 9

Why does thermal pollution occurs?

Answer 9

• Water is used to cool generators in factories

- Hot water is discharged into the water source

Question 10

How does thermal pollution affect the aquatic ecosystem?

Answer 10

• high water temperature –> aquatic animals to die // egg hatches early or fail to hatch
• encorage growth of algae –> covers water surface –> aquatic plants x obtain sunlight for photosynthesis –> O2 level decreases –> plants die –> increase in decomposers –> release more CO2 into water –> BOD level increases

Question 11

Give one difference between in-situ conservation and ex-situ conservation

Answer 11

• In-situ: wildlife species kept in their original habitat (marine parks // wildlife parks)
• Ex-situ: wildlive species move out from their ori habitat (zoo // botanical garden)

Question 12

Define green technology

Answer 12

• Development or application of products. equipment or system to preserve the environment while reducing the impact of human activities.