Why do some codons code for the same amino acid as another codon?
a. it is due to mutations.
b. there are only 20 amino acids and 64 possible combinations
c. each codon is unique and they all code for different amino acids.

B. There are only 20 amino acids and 64 possible combinations

Explanation:

A codon is the combination of three nitrogenous bases, which encode an amino acid. Some codons encode the same amino acid as another codon, this is because there are only 20 amino acids and 64 possible combinations.

Amino acids, in turn, are the organic substances that form proteins that will be responsible for various functions in our body, such as structural, enzymatic, defense, transport and hormonal functions.

explanation:

they can be good for the ecosystem