Final answer:
Using friction to remove vernix caseosa, the waxy protective substance on a newborn's skin, is true. Vernix caseosa protects the fetus's skin in utero and can be gently rubbed off after birth.
Step-by-step explanation:
The statement that you may use friction to remove vernix caseosa from an infant's skin is true. Vernix caseosa is a protective, waxy coating that the sebaceous glands of the fetus secrete to protect its skin. This substance begins to form around the 16th to the 20th week of pregnancy when the fetus's movements are restricted, and it assumes the fetal position. The primary function of vernix is to protect the fetus's skin from the amniotic fluid in utero and to provide lubrication during childbirth. While vernix is beneficial inside the womb, it is common practice to gently rub it off, often during the first bath after birth. Friction is typically used to remove any residual vernix caseosa, though gentle methods are recommended to avoid irritating the newborn’s delicate skin.