The answer is letter A.
<span>Organelles and other cellular material are held within a cell by a cellular membrane. These membranes are what consist of a cell's exterior.
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Your circulatory system consists of your heart, blood vessels and blood, and is responsible for transporting life-giving oxygen throughout your body. When you exercise, your body's need for oxygen increases; the harder you work out, the more oxygen your body demands.
The connection between them is Vitamin D.
Vitamin D can be obtained from food and supplements, or synthesized by our bodies when we receive UV radiation in our skin, which is our major source. However, this vitamin comes <span>inactivated</span> and the only way to activate it is through enzymatic conversion (hydroxylation) in the liver and later in the kidneys.
This vitamin is necessary in the intestines because allows calcium and phosphorus to be observed, leading to normal growth and development of bones and teeth. Without enough vit D, bones become fragile, causing osteoporosis.
Answer: Oh boy this is a lot.
Explanation:
1. Organ
2. Nervous tissue
3. Connective tissue
4. Tissue
5. Respiratory system
6. Epithelial tissue
7. Endocrine system
8. Cells
9. Insulin
10. Homeostasis
11. Muscle tissue
12. Organ system
I hope this helps! :)
