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Answer:</h2><h3>1. four</h3>
Your heart has four separate chambers that pump blood, two on the right side and two on the left.
2. When the ventricle relaxes, the aortic valve closes <em>to prevent blood from flowing back into the ventricle</em>. When the aortic valve is not working properly, it can interfere with blood flow and cause the heart to strain to send blood to the rest of the body.
3. In medicine, a person's pulse is a pressure wave caused by the expansion of the arteries as a result of the circulation of blood pumped by the heart.
4. Capillaries are tiny vessels that branch out from arterioles to form networks around body cells.
Capillaries are very tiny blood vessels — so small that a single red blood cell can barely fit through them.
<em>hope</em><em> </em><em>this</em><em> </em><em>help</em><em>!</em><em> </em><em>^</em><em>^</em>
Answer:
Voluntary muscles are muscles that you control; involuntary muscles are muscles that are controlled by the brain, etc and doesn't need your control in order to contract...
Answer:
The correct answer is ''high survival rates of offspring and the cost of parental care''
Explanation:
Natural selection is the differential reproduction of some genetic variants with respect to others. Natural selection favors individuals who maximize their total reproductive success throughout life, that is, it favors certain phenotypes or variants are associated with greater offspring and / or greater survival, that also means that selection will favor those who stop spending on a particular breed at the right time to invest in another, that is, the amount of energy invested in each of them. This same natural selection also favors those genes that make it effective when the body that carries them is in development to extract all possible parental investment from their parents.
The effect of human activity on the amount of carbon stored in sinks is that humans are pulling out the carbon and burning it at a fast pace through activities like mining. The has greatly contributed to the effects such as global warming. I therefore, think that humans are supposed to seek for alternate sources of energy to prevent these effects of global warming.
