What chemical substance enables the impulse to move from one neuron to the next?

Acetylcholine is a neurotransmitter, which is a chemical substance that plays a crucial role in facilitating communication between neurons. When an electrical impulse reaches the end of a neuron, acetylcholine is released into the synaptic cleft, the gap between two neurons. It then binds to specific receptors on the surface of the next neuron, leading to a continuation of the impulse. This process is essential for the proper functioning of the nervous system, including muscle movement and various cognitive functions.

In contrast, dendrites are the structures that receive signals from other neurons, while axons are the long projections that transmit impulses away from the neuron's cell body. Villi, which are small, finger-like projections found in the intestines, are unrelated to neuronal communication and thus do not play a role in the transmission of impulses between neurons. Understanding the unique functions of these components clarifies why acetylcholine is the correct answer in this context.