The prefix "pil-" is related to which part of the body?

The prefix "pil-" is derived from the Latin word "pilus," which means hair. This prefix is commonly used in medical terminology to denote hair-related concepts, such as "piloerection," which refers to the hair standing up on the skin, often in response to cold or fear. In contrast, the other options refer to different body components: "skin" is associated with the prefix "derm-," "nails" pertain to "ungui-" or "onycho-," and "muscle" correlates with "muscul-." Therefore, choosing the prefix "pil-" specifically connects it to hair, making this the correct association.