whenever humans exhale carbon dioxide, plants take it in and use it to make a mixture of sunlight and water to create nutrients for itself. Once it creates the nutrients it releases oxygen which us humans use to breathe. This operation is called photosynthesis.
Answer:
I do Agree with your statement of growing populations, but I am not sure what else you want me to say.
To be simple and easy, your answer would be:
1. Mars
2. Mercury
3. Venus
