Cardiac muscles are
(a) striated (b) nonstriated
(c) voluntary (d) involuntary

Options

A. a and c are correct
B. b and d are correct
C. a and d are correct
D. a, b and c are correct

Answer

To solve the question regarding the characteristics of cardiac muscles, we will analyze each option provided:

1. **Understanding Cardiac Muscles**:
- Cardiac muscles are specialized muscle tissues found only in the heart. They are responsible for pumping blood throughout the body.

2. **Analyzing the Options**:
- (a) **Striated**: Cardiac muscles have a striped appearance due to the arrangement of sarcomeres, which are the basic contractile units of muscle tissue. Therefore, cardiac muscles are striated.
- (b) **Nonstriated**: This option is incorrect because cardiac muscles do exhibit striations.
- (c) **Voluntary**: Cardiac muscles are not under conscious control; we cannot willfully control our heartbeat. Therefore, this option is incorrect.
- (d) **Involuntary**: Since cardiac muscles function automatically and are not controlled by our conscious mind, they are classified as involuntary muscles.

3. **Conclusion**:
- Based on the analysis, the correct characteristics of cardiac muscles are:
- (a) Striated
- (d) Involuntary

Thus, the answer to the question is: **(a) Striated and (d) Involuntary**.

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