What does the prefix "ex-" indicate in medical terms?

The prefix "ex-" in medical terminology signifies the meaning of "out" or "away from." This prefix is commonly used to indicate a direction or movement away from a particular structure or location. For example, in terms like "excision," it refers to cutting out or removing tissue, which aligns perfectly with the idea of going outward from the body.

In contrast, the other choices represent different concepts that do not align with the definition of "ex-." "Inside" implies movement into or within a structure, which is the opposite of the direction indicated by "ex-." "Insufficient" relates to a lack or deficiency, while "half" refers to a quantity that is divided, neither of which is relevant to the meaning conveyed by the prefix. Thus, "ex-" is correctly recognized as indicating outward movement.