The answer is chemical energy
Permitting the exchange of nutrients and gases between the blood and tissue cells is the primary function of capillaries. Capillaries are the smallest blood vessels , they are only one cell thick, and they act as sites of the transfer of oxygen and other nutrients from the bloodstream to the body tissues. Additionally, they also collect carbon dioxide, waste materials and fluids for return to the veins.
It's a summarization of useless cash spendings, sorted by date.
This is Circulation !!
Pathway of the blood from Heart to Lungs to Heart then the whole body !!
A. Metabolic
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