Which of the following has complete metamorphosis?

The correct answer is beetles, as they undergo complete metamorphosis, which consists of four distinct life stages: egg, larva, pupa, and adult. This process allows for significant changes in form and function between each stage.

During the egg stage, the beetle is in its earliest form, and once it hatches, it enters the larval stage, which often involves growth and feeding with a different morphology from the adult. After the larval stage, beetles enter the pupal stage, during which they undergo a transformation that prepares them for the adult form. Finally, they emerge as adults, ready to reproduce and continue the life cycle.

In contrast, termites, cockroaches, and springtails exhibit incomplete metamorphosis. In these insects, development occurs through three main stages: egg, nymph (which resembles a smaller version of the adult), and adult. Insects that undergo incomplete metamorphosis do not have a pupal stage, which is a critical component in the life cycle of insects like beetles. This distinction highlights the complexity and variety of developmental strategies in the insect world.