What is the term for the nine amino acids that the body cannot manufacture?

Essential aminoacid

Explanation:

Essential aminoacids are those aminoacids which are not synthesized by the body. There are 9 amino acids which are obtain from food. These are valine, tryptophan, methionine, lysine, phenylalanine, threonine, isoleucine, histidine, and leucine.

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.