Brady- and Tachy- denote which concept?

• A. Between two
• B. Against
• C. Slow/fast
• D. Within

Answer: (C)

Brady- and tachy- are speed modifiers. Brady- means slow, tachy- means fast, and they’re used to describe how quickly a process or rate is occurring—most commonly the heart rate. For example, bradycardia is a slow heart rate, while tachycardia is a fast one. These prefixes come from Greek roots: bradys (slow) and tachys (swift). They indicate tempo, not location or direction. Other prefixes describe position or relation, such as inter- meaning between, anti- meaning against, or intra-/end- meaning within, which is why they don’t fit the concept of speed.