Melatonin and thyroxin are examples of

• A. neurons.
• B. glands.
• C. hormones.
• D. stem cells.

Answer: (C)

Verified step by step guidance

1. Identify the key terms in the problem: 'Melatonin' and 'Thyroxin'.
2. Understand that the problem is asking for a classification of these terms.
3. Recall that 'Melatonin' is a hormone that regulates sleep-wake cycles, and 'Thyroxin' is a hormone produced by the thyroid gland that regulates metabolism.
4. Recognize that hormones are chemical messengers produced by glands in the endocrine system, which are released into the bloodstream to regulate various bodily functions.
5. Conclude that both 'Melatonin' and 'Thyroxin' fit the definition of hormones, as they are involved in regulating physiological processes.