Answer:
The pressure differences on either side of the valve.
Explanation:
The heart valves open and close passively because of pressure differences on either side of the valve. When pressure is greater behind the valve, the leaflets are blown open and the blood flows through the valve. However, when pressure is greater in front of the valve, the leaflets snap shut and blood flow is stopped.
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Marine climate tend to has <span>warm winters and cool summers.
Regions with marine climate mostly located in a region with low elevation. Regions with low elevation tend to have higher temperature, but the existence of water near that region even out the temperature which resulted in moderate level of temperature all year long.</span>
The answer is They help control what enters and leaves the cell