Question

4 под буквой a очень срочно пожалуйста

Answer 1

2. Have people walked on Mars? 
Yes, they have.

3. Has the climate changed? 
Yes, it has.

4. Have we protected the enviroment? 
No, we haven't.

5. Has pollution destroyed a lot of trees?
Yes, it has.

6. Has the world stayed the same?
No, it hasn't.