May or may not fly, with vertebra, lay eggs, have feathers.

• A. Reptiles
• B. Birds
• C. Fish
• D. Insectivore

Answer: (B)

Feathers are the giveaway feature. Having feathers identifies birds among living animals, and when you combine that with laying eggs and a backbone, you get birds. The line about “may or may not fly” captures the fact that birds include both fliers and flightless species like ostriches, so flight ability isn’t exclusive to the group but is common. Reptiles also have backbones and lay eggs, but they lack feathers, so they don’t fit the feather criterion. Fish have backbones and lay eggs as well, but never have true feathers. Insectivore describes a diet, not a single vertebrate group, so it doesn’t define the set. Taken together, the traits point to birds.