Final answer:
The whitish, cheeselike substance that fuses with the epidermis of a fetus is called vernix caseosa. It is a protective coating produced by the sebaceous glands to protect the skin within the womb from chapping and to assist in the birth process.a. Vernix caseosa
Step-by-step explanation:
The cheeselike, whitish substance that fuses with the epidermis and serves as a protective coating for a fetus is known as vernix caseosa. This substance is a thick, waxy coating that forms on the fetus to protect the skin from various conditions within the womb, such as chapping or irritation by the amniotic fluid. Vernix caseosa is produced by the fetus's sebaceous glands and is typically seen during weeks 16-20 of gestation. Additionally, it helps to moisturize the skin and may provide lubrication to facilitate childbirth. It's noteworthy that while the vernix is mostly shed before birth, in some cases, especially with premature infants, remnants can still be found after delivery.
Other substances and features that may be present on a newborn include lanugo, which is a fine, colorless hair that covers the fetus's body and is usually shed close to the time of birth. The umbilical cord plays a crucial role in sustaining the fetus, carrying nutrients and oxygen from the mother and removing deoxygenated blood and waste from the fetus.