Select the correct statement from the following .

Options

A. Valves guard the openings in the septum through which the atrium and ventricle are interconnected .
B. Inter - atrial septum and inter - ventricular septum are thick partitions while atrio - ventricular partitions are thin.
C. Mitral valve has two fibrous non - muscular cusps.
D. All of the above .

Answer

To solve the question, we need to analyze each statement provided and determine which one is correct based on our understanding of heart anatomy and physiology.

### Step-by-Step Solution:

1. **Understanding Heart Anatomy**:
- The heart consists of four chambers: the right atrium (auricle), left atrium, right ventricle, and left ventricle.
- There are valves that guard the openings between these chambers to ensure unidirectional blood flow.

**Hint**: Remember the basic structure of the heart and the role of valves.

2. **Evaluating the First Statement**:
- The statement mentions that "valves guard the opening in the septum through which the atrium and ventricles are interconnected."
- This is true because the tricuspid valve (between the right atrium and right ventricle) and the bicuspid (or mitral) valve (between the left atrium and left ventricle) control blood flow between these chambers.

**Hint**: Identify the specific valves and their locations in the heart.

3. **Evaluating the Second Statement**:
- The statement claims that "inter-atrial septum and inter-ventricular septum are thick while atrio-ventricular partition are thin."
- This is incorrect. Both the inter-atrial septum and inter-ventricular septum are thick to withstand the pressure of blood, while the atrioventricular septum (the area where the valves are located) is also thick to support the valves.

**Hint**: Consider the pressure differences in the heart chambers and how that affects septum thickness.

4. **Evaluating the Third Statement**:
- The statement says, "mitral valve has a fibrous non-muscular carc."
- This is also incorrect. The mitral valve consists of two muscular flaps (leaflets) that are indeed muscular and help regulate blood flow.

**Hint**: Recall the structure of the mitral valve and its components.

5. **Conclusion**:
- After evaluating all statements, the first statement is the only correct one. The valves do guard the openings between the atria and ventricles, ensuring proper blood flow.

### Final Answer:
The correct statement is: "Valves guard the opening in the septum through which the atrium and ventricles are interconnected."

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