Where are apocrine glands primarily located on the body?

Apocrine glands are specialized sweat glands primarily located in specific areas of the body, particularly in the axillary (underarm) and genital regions. These glands play a significant role in the secretion of sweat that is thicker and more viscous than that produced by other types of sweat glands, such as eccrine glands. The secretions from apocrine glands are often associated with body odor, as they become the source of bacterial growth when they interact with the skin's microflora.

In contrast, the other areas mentioned in the options do not primarily contain apocrine glands. While eccrine glands are more widely distributed across the skin and found in large numbers on the palms, soles, and forehead, apocrine glands have a more limited distribution, mainly concentrated in the areas mentioned in the correct answer. This specificity is crucial for understanding how the body regulates temperature and produces odorants related to social and sexual signaling.