Read the passage from "a world of animals. just like other aquatic birds, penguins have webbed feet, and like all birds, they lay eggs. some penguins dig a hole in the ground where they will keep their eggs and protect them by sitting on top of the eggs until they hatch. emperor penguins lay just one egg, and the male takes care of the egg by taking it everywhere until it hatches. like other birds, some penguins build nests to house their eggs.
which is the main idea?
A. penguins are a type of bird.
B. penguins care for their eggs.
C. penguins may build nests.
D. penguin feet are webbed.
