Which of the following best defines complete metamorphosis?

Complete metamorphosis refers to the biological process in which an organism undergoes a significant transformation through distinct life stages: egg, larva, pupa, and adult. This multi-stage development allows the organism to experience different forms and functions throughout its life cycle, particularly where the larval stage often serves different ecological roles than the adult stage. For instance, the larval form may focus on growth and feeding, while the adult form is typically geared towards reproduction.

In contrast, the other options lack clarity about the complete metamorphosis process. The definition that mentions only egg and adult overlooks the critical intermediate stages, particularly the larval and pupal forms that are essential to complete metamorphosis. Similarly, a description of transformation without any larval stage suggests a different type of development, possibly referring to simple or incomplete metamorphosis. The choice explaining continuous growth without distinct stages likewise describes a different growth strategy, not characteristic of organisms experiencing complete metamorphosis. Understanding each of these stages and their roles is crucial for distinguishing complete metamorphosis from other developmental processes.