Our Environment — Practice

Question 1

Define an ecosystem.

Accepted Answer

A community of living organisms interacting with their non-living environment.

Question 2

Name the four Rs.

Accepted Answer

Refuse, Reduce, Reuse and Recycle.

Question 3

Which bin does a vegetable peel go into, and which does a newspaper go into?

Accepted Answer

A vegetable peel goes into the green bin for wet waste and a newspaper into the blue bin for dry recyclables.

Question 4

Name four causes of air pollution.

Accepted Answer

Vehicle and factory smoke, burning of garbage or crop stubble, bursting firecrackers, and construction dust.

Question 5

Give three biotic and three abiotic components of a pond ecosystem.

Accepted Answer

Biotic: fish, water plants and insects. Abiotic: water, sunlight and mud.

Question 6

What causes acid rain?

Accepted Answer

Sulphur dioxide and nitrogen dioxide released by vehicles and factories dissolving in rainwater.

Question 7

Name three sources of water pollution and two diseases it causes.

Accepted Answer

Untreated sewage, industrial waste, and agricultural runoff of fertilisers and pesticides. It causes cholera and typhoid.

Question 8

Give two effects of soil pollution.

Accepted Answer

The soil loses its fertility, and harmful chemicals enter crops and reach us through our food. Earthworms and other useful soil life are also killed.

Question 9

Why are the four Rs given in the order Refuse, Reduce, Reuse, Recycle?

Accepted Answer

They run from most to least effective. Waste that is refused never exists, so it costs nothing to handle. Reducing comes next, then reusing, which needs almost no energy. Recycling is last because, although far better than dumping, it still uses energy to process the material.

Question 10

Explain why mixing wet and dry waste ruins both streams.

Accepted Answer

The wet waste soaks the paper and cardboard so they can no longer be recycled, and the dry waste contaminates material that could otherwise have been composted. So neither stream can be processed properly and both go to landfill.

Question 11

Why should dry leaves be composted rather than burnt?

Accepted Answer

Burning releases fine PM2.5 particles, carbon monoxide and toxic gases into the air. Dry leaves are excellent composting material, and composting turns them into nutrient-rich matter for the soil instead.

Practice — Our Environment

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