Question

Which of the following behaviors allows a bird to maintain a constant body temperature in extremely hot weather?

Answer 1

d. All of the above

These behaviors;

Spreading wings
Flattening feathers
panting

are all evolutionary process to maintain body temperature. Birds are warm-blooded animals. Also known as homeotherms, which is defined as having the constant body temperature. This is a vital function for the survival of the specie.

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c. are hollow

The bones of most birds are hollow in order for the weight of the birds to be light for them to fly.