7.

Birds are uniquely classified from other organisms because they all
have wings.
have feathers.
lay eggs.
eat seeds.

The correct answer is: "have feathers." Birds are the only organisms that have feathers, which are essential for their ability to fly. While not all birds have wings that enable them to fly, all birds do have feathers. Laying eggs and eating seeds are also characteristics of many (but not all) bird species, but they are not unique to birds.