Read the following statements (A – D )
(A) QRS complex in ECG indicates ventricular depolarization.
(B) The electrocardiograph machine is used to obtain Electrocardiogram a (ECG ) on graph paper .
(C) During a cardiac cycle , the left ventricular pumps out about 70 ml is of Oxygenated blood which is called the cardiac output .
(D) The second heart sound is associated with the closure of the semilunar valves .
How many statements from the above is /are incorrect ?

Options

A. Two
B. One
C. Four
D. Three

Answer

To determine how many statements are incorrect from the given options (A – D), we will evaluate each statement one by one.

### Step 1: Evaluate Statement A
**Statement A:** QRS complex in ECG indicates ventricular depolarization.
**Evaluation:** This statement is correct. The QRS complex represents the electrical activity associated with ventricular depolarization in an electrocardiogram (ECG).

### Step 2: Evaluate Statement B
**Statement B:** The electrocardiograph machine is used to obtain Electrocardiogram (ECG) on graph paper.
**Evaluation:** This statement is also correct. An electrocardiograph machine records the heart's electrical activity and can display this information either electronically or on graph paper.

### Step 3: Evaluate Statement C
**Statement C:** During a cardiac cycle, the left ventricle pumps out about 70 ml of oxygenated blood which is called the cardiac output.
**Evaluation:** This statement is incorrect. The 70 ml refers to the stroke volume, which is the amount of blood pumped by the left ventricle per beat. Cardiac output is the product of stroke volume and heart rate, not just the volume pumped out in one beat.

### Step 4: Evaluate Statement D
**Statement D:** The second heart sound is associated with the closure of the semilunar valves.
**Evaluation:** This statement is correct. The second heart sound (dub) is indeed produced by the closure of the semilunar valves in the heart.

### Conclusion
After evaluating all four statements:
- Statement A: Correct
- Statement B: Correct
- Statement C: Incorrect
- Statement D: Correct

Thus, there is **one incorrect statement** (Statement C).

### Final Answer
**There is 1 incorrect statement.**

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