What gas do plants take in from the air to make food?

What is the main cause of air pollution in cities?

What gas do humans breathe out?

Which of these can be recycled?

What is the main reason for global warming?

Which of these causes noise pollution?

How can we reduce waste at home?

What causes acid rain?

Which gas protects us from the sun’s harmful rays?

Which of the following is biodegradable?