Which statement is true about essential amino acids?

• A. They must be obtained from the diet.
• B. They can be synthesized by the body.
• C. Alanine is essential.
• D. Lysine is nonessential.

Answer: (A)

The main idea is that essential amino acids must come from the diet because the body cannot produce them in adequate amounts. If the body can’t make enough of these amino acids, they have to be supplied through food to support normal protein synthesis and other bodily functions. That’s why the statement about dietary requirements is true. While many amino acids can be synthesized by the body, some cannot. For example, alanine can be produced by the body, so it’s not essential. Lysine, however, cannot be synthesized in sufficient quantities by humans and is considered essential, unlike nonessential amino acids.