recycling paper and plastic riding a bicycle to school helping seeds to germinate throwing garbage into a stream
I gave my students this multiple choice question: Which human activity often has a harmful effect on the environment?

Only one answer is correct among these 4 choices:
- recycling paper and plastic
- riding a bicycle to school
- helping seeds to germinate
- throwing garbage into a stream

Could you tell me which one is correct?

throwing garbage into a stream