Sunday, 11 February 2018

White-tailed eagle with wings spread being chased by a gull
Birds

Birds are a class of vertebrates. They are bipedal, warm-blooded, have a covering of quills, and their front appendages are adjusted into wings. A few birds, for example, penguins and ostriches, have lost the influence of flight. All birds lay eggs. Since birds are warm-blooded, their eggs must be hatched to keep the fetuses inside warm, or they will die.

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