Which organism's life cycle is described as Egg -> Juvenile -> Adult?

• A. Nematode
• B. Fish
• C. Insect
• D. Plant

Answer: (A)

Life cycles that move from egg to a distinct juvenile phase and then to adulthood are typical of nematodes. After the egg hatches, nematodes go through several juvenile instars (often labeled J1, J2, J3, J4) before reaching the adult stage, so the sequence can be described as Egg -> Juvenile -> Adult.

Insects usually have larval and sometimes pupal stages before adulthood, and fish often pass through various larval or juvenile forms that aren’t simply labeled as a single “juvenile” stage. Plants don’t follow this egg-to-juvenile-to-adult pattern either, since their development typically proceeds from seedling (juvenile) to mature plant without a separate, universally recognized single juvenile stage.