Answer:
Skeletal system provide strength and protection to heart and also produces essential blood cells such as RBC and WBC
Explanation:
All organ systems in our body work in co-ordination with each other. Skeletal system comprised of bones and cartilages while cardiovascular system comprises of hearts, blood and blood vessels. Firstly the skeletal system protects the heart and also assists in its pumping along with muscle. Secondly, the blood cells such as RBC and WBC are circulated by the blood throughout the body. However these cells are produced in the bone marrow (inside the bones)
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Answer:
Natural selection and selective breeding can both cause changes in animals and plants.the difference between the two is that natural selection happens naturally, but selective breeding only occurs when humans intervene. for this reason selective breeding is sometimes called artificial selection.
Explanation:
Hope this helped Mark BRAINLEST!!!
Smoking ruins your lungs making it harder to breath and get oxygen
you need oxygen when you exercise so you don't faint
smokers get less so it is harder for them, its like trying to exercise while breathing through a sponge or a straw os
