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to maintain bone health, fiber is the only vitamin that is synthesized by microbes in the intestine.
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Answer: D) Pulmonary and aortic valves.
Explanation
There are two main heartbeats from a healthy heart.
The first beat is called the S1 or the lub, and it occurs when the atrioventricular valves (comprising the mitral and tricuspid valves) close.
The second beat is called the S2 or the dub, and it occurs when the semilunar valves (comprising the aortic and pulmonary valves) close.
Listening for heart beats is an essential part of cardiac auscultation.
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Capillaries are one cell thick and so this makes them very thin. capillaries are also arranged in networks known as capillary beds, and thus multiple capillaries are spread over a large area.
Lava<span> is molten rock. It is </span>created<span> deep beneath Earth's surface (often 100 miles or more underground), where temperatures get hot enough to melt rock. Scientists call this molten rock magma when it's underground.</span>Lava<span> is molten rock.
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