Answer:
The correct answer is "8".
Explanation:
The formula to calculate the number of peptides that can be synthesized from a certain number of different amino acids is given as follows:
"n^r"
where "n" is the number of amino acids and "r" is the length of the peptide.
In this case,"n" is 2, since the peptides are synthesized with 2 different amino acids: leucine and histidine; and "r" is 3, since the length of tripeptides is 3 amino acids.
Therefore, the number of distinct tripeptides is given by the formula "2^3", which is "8".