Which of following defines what an essential amino acid is? OA.
An essential amino acid means that the body needs it to perform properly, but non-essential amino acids are not needed to
perform properly.
An essential amino acid is an amino acid that the body can produce its self.
OB.
O C.
An essential amino acid is an amino acid that the person can only get from the food he eats.
D.
All of the above

C

Explanation:

essential amino acids cannot be synthesized within the human body . so they have to be taken outside from foods. ( in human)

but non essential amino acids are synthesized in the liver using essential amino acids.

person has to obtain first class proteins such as meat , egg , soya protein in order to get essential amino acids.

but plants synthesize both essential and non essential amino acids within their bodies.

a person needs both essential and nonessential amino acid for his/her function

hope you understood this part :p

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.