The first step in identifying an organism from a pure working culture is to perform a(n) test.

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.

In what for do plants utilize nitrogen? why do they need nitrogen?

What element is able to combine with itself and hydrogen to form large molecules ?