In human beings, the duration of cardiac cycle is

Options

A. 0.08 second
B. 0.5 second
C. 0.8 second
D. 8.0 second

Explanation

To determine the duration of the cardiac cycle in human beings, we can follow these steps:

### Step 1: Understand the Cardiac Cycle
The cardiac cycle refers to the sequence of events that occur during one complete heartbeat. This includes the contraction (systole) and relaxation (diastole) of the heart chambers.

### Step 2: Know the Average Heart Rate
The average heart rate in a resting adult is approximately 72 beats per minute.

### Step 3: Calculate the Duration of One Cardiac Cycle
To find the duration of one cardiac cycle, we can use the formula:

\[ \text{Duration of one cardiac cycle} = \frac{\text{Total time}}{\text{Number of beats}} \]

In this case, the total time is 60 seconds (one minute), and the number of beats is 72.

\[ \text{Duration of one cardiac cycle} = \frac{60 \text{ seconds}}{72 \text{ beats}} \approx 0.833 \text{ seconds} \]

### Step 4: Round the Result
The calculated duration of approximately 0.833 seconds can be rounded to 0.8 seconds for simplicity.

### Conclusion
Thus, the duration of the cardiac cycle in human beings is approximately **0.8 seconds**.

### Final Answer
The correct answer is **0.8 seconds**.

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