Final answer:
Receiving neurons have specialized receptor sites that fit the shape of certain neurotransmitter molecules, allowing for the precise transmission of signals in the nervous system.
Step-by-step explanation:
Receiving neurons have special receptor sites that fit the shape of certain molecules. These receptor sites are specific to the neurotransmitters they bind with, forming a key-and-lock mechanism that ensures the precise transmission of signals across the synaptic cleft. This specificity is critical to the efficient functioning of the nervous system, allowing neuronal signals to be transmitted swiftly and accurately between neurons.