Final answer:
Vernix caseosa is the protective whitish material produced by fetal sebaceous glands, which prevents the fetus's skin from being chapped or irritated by amniotic fluid.
Step-by-step explanation:
Vernix caseosa is a whitish material produced by fetal sebaceous glands. During fetal development, the sebaceous glands secrete this thick, waxy coating known as vernix, which serves as a protective layer for the fetus's skin. It helps to prevent the skin from becoming chapped or irritated by the surrounding amniotic fluid. It's important to note that sebum produced by the sebaceous glands has a role in lubricating the skin and hair and has antibacterial properties, but vernix is distinct in its composition and purpose, directly related to the in-utero environment of the fetus.