Read the following statements and mark the incorrect statement regarding cardiac muscle.

Options

A. It is a contractile tissue present in heart
B. They are not under the control of will of the animals
C. They show relatively rapid contraction
D. Muscle fibers are multinucleated

Answer

To solve the question regarding the incorrect statement about cardiac muscle, we will analyze each of the provided statements one by one.

### Step-by-Step Solution:

1. **Statement 1: "It is a contractile tissue present in the heart."**
- **Analysis:** This statement is correct. Cardiac muscle is indeed a type of contractile tissue that is found in the heart. Its primary function is to pump blood throughout the body.

**Hint:** Remember that cardiac muscle is specialized for the heart's function.

2. **Statement 2: "They are not under the control of will of the animals."**
- **Analysis:** This statement is also correct. Cardiac muscles are involuntary muscles, meaning they operate without conscious control. They function automatically to maintain heart rhythm.

**Hint:** Involuntary muscles are those that cannot be controlled consciously.

3. **Statement 3: "They show rapid contraction."**
- **Analysis:** This statement is correct as well. Cardiac muscles do exhibit rapid contraction and relaxation, which is essential for maintaining a consistent heartbeat.

**Hint:** Consider how the heart needs to pump blood quickly and efficiently.

4. **Statement 4: "Muscle fibers are multi-nucleated."**
- **Analysis:** This statement is incorrect. Cardiac muscle fibers are typically uninucleated, meaning each muscle cell usually has one nucleus. This distinguishes them from skeletal muscle fibers, which are multi-nucleated.

**Hint:** Recall the structure of cardiac muscle cells and their nuclei.

### Conclusion:
The incorrect statement regarding cardiac muscle is **Statement 4: "Muscle fibers are multi-nucleated."**