Synapses facilitate unidirectional neural communication

Steps:

• Statement 1: Synapses ensure one-way impulse travel via presynaptic release to postsynaptic reception.
• Statement 2: Neurotransmitters diffuse across the synaptic cleft to transmit signals.
• Statement 3: Synapses define junctions linking neurons for signal relay.
• All three statements align with synaptic function, confirming A.

Why A is correct:

• Synapses are specialized junctions where neurotransmitters diffuse unidirectionally, per neural transmission principles.

Why the others are wrong:

• B omits statement 3, ignoring the basic definition of synapses as neuronal junctions.
• C omits statement 2, neglecting neurotransmitter diffusion across the gap.
• D omits statement 1, overlooking the unidirectional impulse enforcement.

Final answer: A