Final answer:
A signal travels across a nerve synapse through a chemical process involving the release of neurotransmitters from the axon terminals that then bind to receptors on the next neuron.
Step-by-step explanation:
When considering how a signal travels across a nerve synapse, the correct answer is chemical. The process at a synapse involves the release of neurotransmitters from the axon terminals of the presynaptic neuron into the synaptic cleft. These neurotransmitters then diffuse across the cleft and bind to receptors on the postsynaptic neuron's membrane, thereby transmitting the signal to the next neuron. Although neuronal communication is an electrochemical event, with an electrical portion as the action potential travels down the neuron's axon, the actual crossing of the synapse is a chemical event.
The process that best describes how a signal travels across a nerve synapse is chemical.
At a chemical synapse, neurotransmitter chemicals are released from the presynaptic cell into the synaptic cleft. These chemicals then travel across the cleft to the postsynaptic cell and bind to receptors embedded in its membrane. This binding of neurotransmitters triggers a response in the postsynaptic cell, allowing the signal to be transmitted.