What type of glands are located in the armpit and groin, secreting sweat and substances that lead to body odor?

The apocrine glands are responsible for the secretion of sweat and other substances that contribute to body odor, particularly in areas like the armpit and groin. These glands become active during puberty and are typically associated with hair follicles. The sweat they produce is thicker and contains proteins and fatty acids, which, when broken down by bacteria on the skin, can lead to the characteristic scent of body odor.

Eccrine glands, in contrast, are found throughout the body and primarily secrete a watery, odorless sweat that is important for regulating body temperature. Sebaceous glands produce oil (sebum) for moisturizing the skin and hair, and they do not contribute to sweat production. Merocrine glands is another term often used interchangeably with eccrine glands but does not specifically pertain to the apocrine sweat production associated with body odor.

Thus, the recognition of the specific role of apocrine glands in sweat production and their location in sweat gland-rich areas directly explains why this option is the correct choice regarding body odor and sweat secretion.