Neurotransmitters are released from neurons in response to the increase in intracellular concentration of what ion?

Neurotransmitters are released from neurons in response to the increase in intra-cellular concentration of CALCIUM IONS

Explanation:

Calcium ion are vital in the release of neurotransmitters. When action potential reaches the terminal of a neuron, the voltage-dependent calcium ions are activated, there is therefore the influx of calcium ions. When calcium channels are blocked, there is the inhibition of neurotransmitter release from the neurons. Calcium channels are discovered to be located near the active zones of vesicular membranes and it has been found that the influx of calcium ions is far greater at the active zones than elsewhere in the neurons. So the observation of large influx of calcium ions in the active zones of neurons is consistent with the release of neurotransmitter as action potential is generated in the neurons.

c. genetic engineering

explanation:

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?