Ответ:

2. If we dump all sorts of chemicals into rivers we won't be able to swim in them in the future.

3. If we don't stop  cutting down so many trees we would endanger our oxygen supply.

4. If the global temperature rises, sea levels will rise too.

5. People will run out of drinking water one day  if they don't use it more rationally.

6. If the human wants to help the planet  then he has to change his habits.

Объяснение: