Assertion :- Nerve impulse conduction is one way conduction.
Reason:- Neurotransmitters are only present at axon terminals.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

To solve the question regarding the assertion and reason, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Nerve impulse conduction is one way conduction." This means that once a nerve impulse is generated, it travels in a single direction along the neuron, from the dendrites to the axon terminal.

2. **Understanding the Reason**:
- The reason provided is "Neurotransmitters are only present at axon terminals." Neurotransmitters are chemical messengers that are released from the axon terminal to transmit signals to the next neuron or target cell.

3. **Analyzing the Relationship**:
- The assertion is true because nerve impulses indeed travel in one direction due to the structure of the neuron and the way signals are transmitted.
- The reason is also true because neurotransmitters are primarily released from the axon terminals to communicate with adjacent neurons.

4. **Evaluating the Explanation**:
- While both the assertion and reason are true, the reason does not directly explain why nerve impulse conduction is one-way. The one-way conduction is primarily due to the refractory period of the neuron and the unidirectional flow of ions during action potentials.

5. **Conclusion**:
- Since both the assertion and reason are true, but the reason does not serve as a correct explanation for the assertion, the correct answer is that both are true, but the reason is not the correct explanation of the assertion.

### Final Answer:
- The correct option is: 1. If both assertion and reason are true and reason is not the correct explanation of assertion.