Which of the following is NOT a stage in complete metamorphosis?

In the context of complete metamorphosis, the life cycle of insects consists of four distinct stages: egg, larva, pupa, and adult. Each of these stages represents a significant transformation as the organism develops from an immature form to an adult.

The nymph stage is characteristic of incomplete metamorphosis, which differs from complete metamorphosis. In incomplete metamorphosis, an insect's growth process includes just three stages: egg, nymph, and adult. During the nymph stage, the insect resembles a smaller version of the adult but lacks fully developed wings and reproductive capabilities.

In contrast, complete metamorphosis features the larval stage where the organism undergoes various changes before becoming a pupa. The pupa stage involves a transformative process where the larva eventually morphs into the adult form. Each of these stages plays a crucial role in the lifecycle of insects undergoing complete metamorphosis, highlighting the significant biological changes that occur.

Thus, the nymph stage is not part of complete metamorphosis, making it the correct response to identify which option does not fit within this life cycle.