The prefix "exo-" can be understood to mean?

The prefix "exo-" is derived from Greek, meaning "outside" or "external." It is often used in medical terminology to describe something that is situated outside of a given structure or area. For example, in the term "exoskeleton," it refers to a skeleton that is outside the body, as opposed to an endoskeleton, which is internal. This understanding of the prefix helps clarify its usage in various medical contexts, where it denotes external relations or locations. In contrast, the other options represent different directions or states that do not align with the meaning of "exo-."