Name the neurotransmitter released at the synapse by the sympathetic nerve fibres.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the name of the neurotransmitter released at the synapse by sympathetic nerve fibers.

2. **Identifying the Role of Sympathetic Nerve Fibers**: Sympathetic nerve fibers are part of the autonomic nervous system and are responsible for preparing the body for 'fight or flight' responses during stressful situations.

3. **Defining Synapse**: A synapse is the junction between two neurons, where the transmission of signals occurs. Neurotransmitters are released into this gap to facilitate communication between neurons.

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