Final answer:
Eccrine glands produce mostly water-based sweat which is generally odorless. The oily secretions from apocrine glands, found in the armpits and groin, are broken down by skin bacteria leading to body odor. Good hygiene practices can help control bacteria and reduce odor.
Step-by-step explanation:
The sweat glands in which the secretion is typically odorless are the eccrine glands. These glands are responsible for most of the sweat on your body and their secretion is mostly water with some salts. When bacteria are present on the skin, particularly in areas where apocrine glands are located like the armpits and groin, they can cause odor. The apocrine glands produce a thicker, oily secretion rich in organic compounds. When these secretions are released, local bacteria on the skin break them down, and it is this process that generally causes body odor. Regular hygiene practices such as bathing can help manage bacteria and reduce body odor.