Sure! Here's the rewritten version of each sentence:

1. If we recycle more, we will be able to protect the environment.
2. If we don't control overfishing, it will damage marine life.
3. If you throw garbage into rivers and lakes, you'll make them dirty.
4. Unless we stop polluting the environment, we will get more health problems.
5. Unless we stop water pollution, we won't have enough food and water.