Answer the following question given this paragraph: 

The main reason that insects have been so successful is their ability to fly. Insects are the only invertebrates that can fly and the first animals to evolve flight. Flight has important advantages. It’s a guaranteed means of escape from nonflying predators. It also aids in the search for food and mates.


Q: What are the only invertebrates that can fly?

 Choices:

- birds

- amphibians

- mammels

- insects

A:
insects
