Which prefix means Good, Normal?

• A. eu-
• B. sub-
• C. intra-
• D. end-

Answer: (A)

This prefix signals goodness, wellness, or a normal state. eu- means good, well, or normal, as shown in eupnea (normal breathing), euthyroid (normal thyroid function), and euphoria (a feel-good state). The other prefixes point to location or position rather than quality: sub- means under, intra- means within, and endo- (end-) means inside. So eu- is the best fit for “good, normal.”