<span>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 </span><span>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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<span>c. are hollow
</span>
The bones of most birds are hollow in order for the weight of the birds to be light for them to fly.
Hydrophilic heads, hyrdophobic tails. Heads are made of phosphate and the tails are made of lipids.
