Which prefix indicates a process of going outward?

The prefix that indicates a process of going outward is "E-." This prefix derives from the Greek word "ex-" or "ek," meaning "out" or "away." It is commonly used in medical terminology to describe processes or conditions that move away from a center or point of origin. For example, in terms like "eject," the prefix implies a forceful move outward from a contained space.

The other prefixes do not convey the same meaning. "Endo-" refers to something situated within or inside, which denotes an inward orientation rather than outward. "Circum-" means around or about, suggesting an encircling action but not specifically an outward motion. "Di-" typically indicates a doubling or separation, not directly relating to moving outward. Hence, "E-" is the appropriate choice for indicating a process going outward.