Answer: Amino acid.
- A Carbohydrate
- B Nucleic acid
- C Fatty acid
- D Amino acid
Correct answer: D. Amino acid
Explanation: Hormones are chemically diverse - proteins/peptides, steroids, and amino-acid derivatives such as thyroxine and adrenaline.
The hypothalamus releases hormones that direct the pituitary, which releases its own trophic hormone to a target gland; that gland's hormone output then feeds back (dashed lines) to suppress both the pituitary and hypothalamus once levels are sufficient - a self-correcting loop running the entire endocrine system.
Concept context
The endocrine glands, hormone classification and mechanism of action, and negative feedback regulation.