Which insects develop without metamorphosis, having instars that resemble adults?

The correct answer is silverfish, as they are an example of insects that undergo a form of development called ametabolism, which means they develop without undergoing metamorphosis. In this process, silverfish hatch from eggs and grow into adults through a series of life stages known as instars, during which they closely resemble the adult form. This lack of a dramatic transformation is a key characteristic of ametabolous insects.

In contrast, butterflies represent an example of complete metamorphosis, where they undergo distinct stages: egg, larva (caterpillar), pupa (chrysalis), and then adult. Cockroaches and ants, on the other hand, exhibit incomplete metamorphosis, involving a nymph stage that, while similar to the adult, does not look exactly the same and develops through several stages before reaching maturity. Thus, the unique developmental process of silverfish distinctly identifies them as insects that develop without metamorphosis, closely resembling adults at every instar stage.