Unipolar neurons with an axon and no dendrite are present in :

Options

A. Embryos
B. Dorsal root ganglia of spinal cord
C. Brain
D. Retina

Answer

### Step-by-Step Solution:

1. **Understand the Question**: The question is asking about the presence of unipolar neurons that have one axon and no dendrites.

2. **Define Unipolar Neurons**: Unipolar neurons are a type of neuron that has a single process extending from the cell body. This process splits into two branches: one that acts as a dendrite and the other as an axon. However, in the context of this question, we are focusing on unipolar neurons that have only an axon and no dendrites.

3. **Analyze the Options**:
- **Option 1: Embryo**: Unipolar neurons are indeed present in embryos during the early stages of development.
- **Option 2: Dorsal Root Ganglia of Spinal Cord**: This region contains primarily pseudounipolar neurons, which are similar but not exactly the same as unipolar neurons.
- **Option 3: Brain**: The brain predominantly contains multipolar neurons.
- **Option 4: Retina**: The retina contains bipolar neurons and other types, but not unipolar neurons.

4. **Select the Correct Answer**: Based on the analysis, the correct answer is **Embryo**, as unipolar neurons are typically found during embryonic development.

5. **Conclusion**: Therefore, the answer to the question is that unipolar neurons with an axon and no dendrites are present in **Embryos**.