What would happen to the propagation of a neural impulse if the membrane potential (voltage) at the synaptic terminal did not cross the threshold to open voltage-gated calcium channels

Hello the options related to your question is missing attached below are the missing options

answer : Calcium channels would remain closed, causing the neural impulse to travel back to the cell body. ( B )

Explanation:

When the membrane potential at the synaptic terminal does not cross the given threshold to an open Voltage-gated calcium channels, the propagation of the neural impulse will travel back to the cell body and this is caused by the calcium channels to remaining  closed

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.