Question

define heartbeat in science​

Answer 1

Answer:

A heartbeat is a two-part pumping action that takes about a second. As blood collects in the upper chambers (the right and left atria), the heart's natural pacemaker (the SA node) sends out an electrical signal that causes the atria to contract.

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Answer 2

Answer:

A heartbeat is a two -part pumping action that takes a second. about