Which of the following amino acids is essential for humans?

• A. E
• B. C
• C. Y
• D. W

Answer: (D)

Verified step by step guidance

1. Understand the concept of essential amino acids: Essential amino acids are those that cannot be synthesized by the human body and must be obtained from the diet.
2. List the essential amino acids for humans: There are nine essential amino acids, which include histidine (H), isoleucine (I), leucine (L), lysine (K), methionine (M), phenylalanine (F), threonine (T), tryptophan (W), and valine (V).
3. Identify the amino acids given in the problem: The amino acids provided are E (Glutamic acid), C (Cysteine), Y (Tyrosine), and W (Tryptophan).
4. Compare the given amino acids with the list of essential amino acids: Check which of the given amino acids is present in the list of essential amino acids.
5. Conclude which amino acid is essential: From the comparison, determine that tryptophan (W) is the essential amino acid among the options provided.