Converts solar energy to chemical energy

Astudy was performed on 20 trees to test the effectiveness of a new fertilizer. the results of this specific study is brought into question. what would possibly improve the reliability of the results?

Animal bodies (and even plant bodies for that matter) are complex enough that life couldn't exist without enzymes. enzymes are usually large, complex biological catalysts that are expensive to make. enzymes speed up the rate of chemical reactions without being used up during the reaction (they can be reused many times). they are highly specific in the reactions they regulate. knowing what enzymes are and how they function, why does this explain why complex life forms could not exist if there were no enzymes.

If you have a difficult time knowing where your hand is without looking at it you may be having a problem with your what ?