I believe a. is the answer
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Answer:D
Explanation:
Hibernation is an innate behavior. It is not learned after birth. Animals that hibernate are born with an internal sense, or instinct, that tells them.
Hope This help :P
True, it would take a couple of minutes to reach the brain once its in the blood stream
When the skin is exposed to ultraviolet rays, the skin produces a molecule that is turned into Vitamin D.
Sun is the source of ultraviolet rays important for Vitamin D production. Due to this reason, in the case of Vitamin D deficiency, it is recommended by doctor's to absorb sunlight by skin. The Vitamin D production occurs specifically by UV B rays rays which lie in the range of 290-315 nanometer.
The chemical 7-dehydrocholesterol absorbs these rays and convert to previtamin D3. Further, previtamin D3 isomerizes to Vitamin D. Other than sunlight, Vitamin D can be taken through diet. The sources include seafood like fish, fish oil, dairy products, beef liver etc. Vitamin D is required for bone and teeth formation, muscle contraction, immune system etc.
Learn more about Vitamin D -
brainly.com/question/4551554
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Physical symptoms may be:
<em>* low energy
</em><em>* loss of sleep
</em><em>* headaches
</em><em>* nausea
</em>
=)