What does the prefix "De-" usually signify?

The prefix "De-" typically signifies the idea of removing, reducing, or reversing something. In medical terminology, it often refers to the process of taking away or down from a certain state. For instance, in words like "dehydrate," it indicates the removal of water. Similarly, in "decontaminate," it conveys the action of removing contaminants. This prefix is common in various contexts, including pharmacology and biology, where it implies a negative or opposite action.

The other options refer to different actions that do not align with the fundamental meaning of "De-." Terms related to increasing, adding, or replacing do not connect to the concept of removal or reduction that "De-" embodies. Therefore, identifying that "De-" relates to the idea of down or removal is crucial for understanding its role in medical and scientific terminology.