MCQOPTIONS
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				| 1. | 
                                    Cardiac muscle contracts due to______________? | 
                            
| A. | Extracellular Ca+2 | 
| B. | Sarcoplasmic ca+2 | 
| C. | Extracellular Na+ | 
| D. | Intracellular Na+ | 
| Answer» B. Sarcoplasmic ca+2 | |