Why is it important for a cell to control what enters and leaves its structure

If the birth rate of a population of dolphins is 2.0, the death rate is 0.5, and the population size is 100, what is this dolphin's population growth?

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.

The idea of spontaneous generation was disproved by in a experiment involving jars of meat