The heart gets its nourishment through nutrient rich blood through the <span>myocardium. Eating heart healthy foods full of omega 3's will help keep the heart healthy.
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It would be Carbon Dioxide or CO2. hope that this helped hon :)
I think it isn't right to claim that an attribute developed so the species included can survive better, qualities advance since people with that characteristic survive better and duplicate more.
I hope the answer will help you.