Plateau phase of cardiac cycle is due to -

Ans. is 'c' i.e., Ca2+ o Phase 0 (phase of rapid depolarization)- opening of fast sodium channels with Na4 influxo Phase 1 (initial phase of rapid repolarization)- closure of fast sodium channelso Phase 2 (plateu phase)- opening of voltage gated slow Ca++ channels with calcium influx.o Phase 3 (final repolarization)- opening of K+ channels with K+ efflux.o Phase 4- Resting membrane potential.