Answer
Answer; (b).
The result of male or female hormones increasing at puberty
Work Step by Step
For males secondary characteristics include facial hair, development of heavier skeletal musculature, deepening of the voice, increase in size of Adam's apple (thyroid ligament of the larynx), growth of more and courser body hair. These changes are generated and supported by increased secretion of androgens mainly the hormone testosterone.
For females, the secondary characteristics include the growth of pubic hair, and breasts; the widening of the pelvis and the morphing into a softer more rounded shape with more subcutaneous fat. These changes in the female are produced and maintained by increased secretion of estrogens, primarily estradiol.
Estrogens and androgens are produced by glands and tissues ( testes, ovaries, adrenals and fat) in both sexes, and the levels vary with age . However, the ratios vary with sex. For instance, adult females produce about 14 times as much estrogens as men do . On the other hand, adult males produce about 20 times as much testosterone as adult females do.
