What do we call electrical messages that are sent down an axon of a neuron?

When the action potential reaches the axon ending, it causes another ion (calcium, Ca++) to enter the cell, which in turn causes the vesicles -- the tiny bubbles full of neurotransmitters -- to release their contents into the synaptic gap

I forgot it’s something like I can’t think of the name

The punnett square is the device used to predict genetics.