During the spike of an action potential in a cardiac muscle cell
a. there is a rapid influx of Na+ into the cell.
b. Ca2+ moves out of the cell into the extracellular fluid.
c. K+ channels open to let K+ move into the cell.
d. both Na+ and Ca2+ move into the cell at the same time.
e. Na+ moves out of the cell into the extracellular fluid.
Answer: a. there is a rapid influx of Na+ into the cell.
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Answer the following statement true (T) or false (F)