Which of the following is true about lanugo?

Lanugo is a fine, soft hair that covers the body of a fetus, and it plays an important role during the development process. One of the main functions of lanugo is to help regulate body temperature. This is particularly significant for preterm infants who may not yet have developed adequate layers of fat for insulation. The presence of lanugo helps provide some warmth and insulation to the baby's body as it is still adjusting to life outside the womb.

While lanugo is a temporary feature, it typically disappears before birth or shortly thereafter, and its absence is not a sign of any health issue in a well-developed newborn. The other options relate to misunderstandings about lanugo, such as its permanence or its association with malnutrition or skin irritation, all of which do not accurately describe this specific type of hair in infants.