Answer to Question 1
ANS: A
Unlike those of other muscle tissues, however, cardiac contractions cannot be sustained or teta-nized because myocardial tissue exhibits a prolonged period of inexcitability after contraction. The period during which the myocardium cannot be stimulated is called the refractory period.
Answer to Question 2
ANS: A
Inherent rhythmicity or automaticity is the unique ability of the cardiac muscle to initiate a spon-taneous electrical impulse.