Question

Primary sex determination results from DNA directing the production of either testes or ovaries in the embryo. What then determines secondary sexual characteristics?

a) Hormonal changes during puberty.
b) Genetic mutations in sex chromosomes.
c) Environmental factors during early development.
d) Diet and nutrition during adolescence.

Answer 1

Secondary sexual characteristics are determined by hormonal changes during puberty, not by genetic mutations, environmental factors, or diet and nutrition.

Step-by-step explanation:

Secondary sexual characteristics are determined by hormonal changes during puberty. Mammalian sex determination, which dictates whether the developing embryo will have testes or ovaries, is largely controlled by the presence of X and Y chromosomes. However, once the primary sex organs are developed, it is the release of sex hormones—such as testosterone in males and estrogen in females—during puberty that leads to the development of secondary sex characteristics.

These characteristics include the development of body and facial hair, maturation of the reproductive organs, and the emergence of breasts. The hormones responsible for these changes originate from the gonads (testes or ovaries), which begin to significantly produce these hormones in response to stimulation by other hormones from the hypothalamus and pituitary gland.