Final answer:
Vellus hair on the human body is also known as lanugo hair when referring to the fetal stage, being fine and colorless until shed close to birth. It's distinct from terminal hair, which is thicker and pigmented, typically found after puberty.
Step-by-step explanation:
Vellus hair is the short, fine, and downy hair that can be found on the human body. Of the options provided, it is also known as lanugo hair when it refers to the fine, colorless hair that covers a fetus's face and body until it is shed close to the time of birth. It is important to differentiate between the different types of hair: terminal hair is thick, long, and pigmented, often found on the scalp and as body hair during and after puberty; androgenic hair is a type of terminal hair influenced by androgens, which appears during and after puberty; and sebaceous hair is not a correct term for any hair type on the human body. Vellus hair in adults is different from lanugo hair on a fetus but is often mistaken due to its similar appearance.