Cooper is 13 years old, and he has recently noticed some remarkable changes in himself. Over the past few months his voice has started to change, growing deeper. He has begun to grow pubic hair, as well as the beginnings of a facial beard. He is also filling out, with his muscles developing rapidly. These changes in Cooper are probably due to the action of the __________.
A) gonads
B) thyroid gland
C) pineal gland
D) adrenal gland

Question

Quizplus · Accepted Answer

The changes in Cooper are due to the action of his gonads, which are producing increased levels of testosterone. This hormone is responsible for the development of secondary sex characteristics in males, such as deeper voices, pubic hair, and muscle growth. The thyroid gland, pineal gland, and adrenal gland are important parts of the endocrine system, but they do not play the same role as the gonads in puberty.

Cooper Is 13 Years Old, and He Has Recently Noticed