What is indicated by the prefix "Tachy-"?

The prefix "tachy-" indicates a condition of increased speed or rapidity. In medical terminology, it is commonly used to describe elevated heart rates or quickening of any physiological process. For example, "tachycardia" refers to an abnormally fast heart rate. Understanding the meaning of this prefix is crucial for interpreting medical terms correctly, particularly those relating to vital signs and their relevance to patient health.

The other choices pertain to different states of speed; for instance, "slow" would relate to the prefix "brady-," which is specifically used to denote slowness in a physiological context. "Average" and "normal" do not convey any indication of speed or pace, making them unsuitable in this context.