The answer is <span>B. contains enzymes that begin the breakdown of proteins.
Saliva is watery substance secreted by salivatory glands. <em>It cleanses the mouth</em> and maintenance oral hygiene. <em>It moistens the food</em>, so the created food bolus could easier pass into the esophagus. It also <em>carries food chemicals to taste receptors</em> so they can be tested. It contains enzymes involved in the food digestions. Some of them are amylase, which begins the breakdown of the starch, and lipase, which begins the breakdown of triglycerides. <u>There are no enzymes in the saliva that break down proteins</u>.</span>
Three major types of RNA are mRNA, or messenger RNA, that serve as temporary copies of the information found in DNA; rRNA, or ribosomal RNA, that serve as structural components of protein-making structures known as ribosomes; and finally, tRNA, or transfer RNA, that ferry amino acids to the ribosome to be assembled .
RNA carries genetic information from the nucleus to ribosomes for the synthesis of proteins; while tRNA carries specific amino acids to the ribosomes to assist the protein biosynthesis, and on the other hand, rRNA provides the structural framework for the formation of ribosomes.
