What two features distinguish mosquitoes from other closely related insects?

The distinction of mosquitoes from other closely related insects can be attributed to the unique characteristics that are prominent in females. The presence of a distinct blood-sucking proboscis is a key feature, as it allows female mosquitoes to feed on blood, which is essential for their reproductive cycle. In addition to this, mosquitoes are also covered in numerous scales on their bodies, which contribute to their unique appearance and may play a role in camouflage and water repellent properties. These two features, the specialized feeding apparatus and the scaly body texture, form a clear identification of mosquitoes within the larger group of insects they are related to.

Other options focus on characteristics that do not apply specifically or consistently to mosquitoes as distinguishing features among insects. For instance, male mosquitoes do not commonly exhibit a large body size or distinctive coloration compared to females across all species. Similarly, egg-laying behavior and larval size can vary widely among different insect groups and do not specifically define mosquitoes. This further reinforces why the correct answer highlights the combination of the proboscis and body scales as the distinguishing traits.