The answer is C. dreaming causes major muscle contractions triggered by the activation of the alpha motoneurons in the spinal cord.and tossing and turning.
Answer: Yes, activities like aerobics help to have a healthy heart and that is why I like to do them.
Explanation: The exercises not only help the physical appearance but also health. A healthy heart is vital so that a person can live his daily life in a normal way and without any type of problems. In my case, I like to do aerobics or some type of cardio since these exercises help to maintain a young heart. Remember that these activities must be accompanied by a good diet.
Answer:
There are air filters to purify the air and water filters to clean the water. Well, the kidneys are like a filtering system, too. They contain nephrons, which filter waste from the blood in two stages. First, nephrons take waste as well as needed materials out of blood. Then, the materials the body needs (like water and glucose) are returned to the blood and wastes are eliminated from the body. This is one way the kidneys maintain homeostasis. The kidneys also regulate the amount of water in the body. The amount of water the kidneys return to the blood depends on the conditions inside and outside of the body. This is another way the excretory system maintains homeostasis. For example, you will make more urine on a cool day when you have drunk a lot of water than you will on a hot day when you've hardly had anything to drink.
(I answered a question similar to this some time ago so you might also find it there.) Hope It Helps!
We can’t do that we just can answer questions you ask because they are millions of test…
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.
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