If your good with bio and photosynthesis help a girl out!

Coquina, a type of limestone, forms from shell fragments that settle on the ocean floor. what type of rock is coquina?

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.

What enzyme is most important for dna replication and why?