What substance is found in synaptic vesicles of the axon terminal

I believe synaptic vesicles contain neurotransmitters.

Explanation:

In the far end of a neuron, there is the branch like ending with called the axon terminals. This is where neurons communicate with other neurons through a space called a synaptic cleft with the aid of neurotramitters. To better understand the significance of the synaptic vesicles, I have explained the functioning of the terminal before with an attached picture.

When a neuron receives a signal/stimulus from the external environment via the dendrites, it converts this signal into a nerve impulse in the cell body. The impulse. The impulse then travels along the myelinated axon to reach the end of the neuron called the axon terminal which links up with the next organ or neuron. When the impulse reaches the membrane of the axon terminal, it stimulates the opening of voltage gated calcium ion channels. This causes an influx of calcium ions inside the membrane of the cell and that stimulates synaptic vesicles containing chemicals called neurotransmitters to move towards the membrane of the axon terminal. When they reach the membrane, they fuse with it and rapture releasing neurotransmitters into the synaptic cleft. The neurotransmitters bind to ligand gated ion channels on the second neuron or the second cell causing a response in it. The voltage gated channels close and the synaptic vesicels that were not opened up continue holding the remaining neurotransmitters.

option c is the correct answer.

a physical change is being made.