An enzyme, such as rna polymerase, that is needed by the cell in large amounts and must usually be present would be called?

Constitutive enzyme

Explanation:

Constitutive enzymes are synthesized by the cell at all times and are required in large amounts. In contrast, Inducible enzymes are synthesized only when required depending upon the availability of substrate and other conditions in the cell.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.