Amino acids joining together to make a peptide is a good example of a reaction.

a) synthesis
b) exchange
c) decomposition
d) reversible

Synthesis

Explanation: Amino acids are building blocks of proteins. They are joined together by a chemical bond formed between the carboxyl group of one amino acid with the amino group of another amino acid to form a peptide bond. This reaction is a dehydration synthesis reaction.

if you know your abc's you should be able to get your answer or just use google