The heart plays a major role in the circulatory system. Which of the following statement(s) is/are correct?
A. An average heartbeat is 72 times per minute.
B. Heartbeat decreases when in fear.
C. The heartbeat of infants is more than adults.
D. The human heart has four chambers.
1
A, C and D
2
B, C and D
3
A, B and D
4
All of the above