Spindle cells are found in the blood of

Options

A. mammals
B. fishes and amphibians
C. reptiles and birds
D. both (2) and (3)

Answer

### Step-by-Step Solution:

1. **Understanding Spindle Cells**:
- Spindle cells are specialized cells that are longer than they are wide. They are often associated with connective tissues and can be found in both healthy tissues and tumors.

2. **Identifying the Common Type**:
- The most common type of spindle cell is the fibroblast, which plays a crucial role in connective tissue.

3. **Function of Spindle Cells**:
- These cells are involved in various functions, including blood clotting. They are important for maintaining the structural integrity of tissues.

4. **Presence in Different Animals**:
- Spindle cells can be found in the blood of various animal groups. Specifically, they are present in fishes, amphibians, reptiles, and birds.

5. **Analyzing the Options**:
- The question provides four options:
- (1) Mammals
- (2) Fishes and Amphibians
- (3) Reptiles and Birds
- (4) Both two and three
- Since spindle cells are found in fishes, amphibians, reptiles, and birds, the correct answer must include options (2) and (3).

6. **Conclusion**:
- Therefore, the correct answer is option (4), which states that spindle cells are found in both fishes and amphibians as well as reptiles and birds.