D: All the variables are controlled except one.
Answer:
They need food in order to gain the initial energy they need.
Explanation:
Plants unlike humans don't get food by primary sources (aka, hunting). instead they retrieve their food from the suns rays. Without the suns rays they are able to convert this energy into glucose for themselves, and will essentially die because they do not have that source of food to give them the energy they need to survive.
They are related because they are all in the same blood or family you breathe in oxygen and remove carbon dioxide the carbon dioxide it helps other stuff in the ecosystem to survive or live so its like this people breathe oxygen while plants breathe carbon dioxide.
