Which prefix indicates something happens "beneath"?

The prefix that indicates something happens "beneath" is "sub." This prefix originates from Latin, where it means "under" or "below." It is commonly used in various English words to convey the idea of being underneath or lower in position, such as in "submarine" (meaning under the sea) or "subterranean" (meaning beneath the earth's surface).

The other choices represent different concepts; "post" refers to things that happen after or later, "inter" relates to things occurring between or among, and "mal" generally indicates something bad or harmful. Understanding prefixes is crucial as they provide context that can significantly change the meaning of a root word, reinforcing the importance of selecting the correct prefix to convey the intended meaning accurately.