What characterizes complete metamorphosis in insects?

Complete metamorphosis in insects is characterized by development through four distinct life stages: egg, larva, pupa, and adult. This type of metamorphosis allows for significant changes in form and function at each stage. For example, the larval stage often involves feeding and growth, while the pupal stage is a time of transformation where the insect undergoes crucial changes to emerge as an adult with a completely different morphology and ecological role.

In contrast, other life development patterns, such as continuous growth without distinct stages or direct development from egg to adult, do not include intermediate forms like larvae and pupae, which are integral to complete metamorphosis. These options reflect simpler life cycles that lack the complexity and dramatic changes that characterize insects undergoing complete metamorphosis. Only having two life stages, such as egg and adult, also does not capture the essence of complete metamorphosis since it omits the essential larval and pupal stages that define this process.