Which suffix signifies "to kill"?

The suffix that signifies "to kill" is indeed -cide. This suffix is derived from the Latin word "caedere," which means "to kill." It is commonly used in various medical and scientific terms to indicate the act of killing or destroying something. For example, "pesticide" refers to a substance used for killing pests, and "bactericide" refers to an agent that kills bacteria.

In contrast, the other suffixes listed do not have the same meaning. The suffix -crit relates to separation or a selection process, often used in terms like "hematocrit," which pertains to the proportion of blood volume that is occupied by red blood cells. The suffix -clusis pertains to closure or a condition that leads to closure, while -clasia involves breaking or deforming, particularly in medical contexts that describe surgical procedures. Understanding these distinctions helps clarify why -cide is the appropriate choice for indicating a killing action.