<span>Platelet is a term that is not used to refer to white blood cells. Platelets are the smallest of all blood cells, and make up a very small fraction of blood volume. The function of platelets is to prevent bleeding, whereas the function of white blood cells is to fight off infection and increase immunity to disease.</span>
<span>Once you make a career choice, it should never be changed.
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Your heart rate is increased during physical activity to increase cardiac output and deliver the blood flow needed to the muscles to carry out those activities. Your heart itself is a muscle, and also gets a workout during exercise. The job of the heart is to get more blood to the body's muscles when they work hard. Hope this helped.
