<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.
Answer:
C. A chain of amino acids
Explanation:
Proteins are made up of hundreds or thousands of smaller units called amino acids, which are attached to one another in long chains. There are 20 different types of amino acids that can be combined to make a protein. ... These proteins bind and carry atoms and small molecules within cells and throughout the body.
