Answer:
The intervertebral discs of the spinal column and 'long bones' such as the femur and tibia.
Explanation:
<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
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The bones of most birds are hollow in order for the weight of the birds to be light for them to fly.
During that process light energy becomes food for plants
