Choose the correct answer A, B, C, or D.

1. When humans use a natural habitat for farming and housing, they cause _______.

A. climate change

B. global warming

C. habitat loss

D. ecological balance

2. When Earth's average temperature increases, we face _______.

A. ecological balance

B. global warming

C. pollution

D. protection

3. Each of us can lend a hand to _______ the natural environment.

A. hunt

B. change

C. preserve

D. pollute

4. We can keep a(n) _______ by stopping hunting and cutting down trees.

A. ecological balance

B. habitat loss

C. climate change

D. nature reserve

5. One way to _______ Mother Earth is by planting more trees.

A. keep

B. harm

C. provide

D. protect