Answer: First Question.
A. PARASYMPATHETIC BRANCH
Second Question (Question 3)
D. THE MOLECULAR GATES OPEN TO ALLOW SODIUM IONS INTO THE NEURON
Explanation:
PARASYMPATHETIC BRANCH
The Parasympathetic Nervous which at times is referred to as the "rest and digest" system is one of 3 divisions in the Autonomic Nervous System.
It conserves energy as it slows the heart and increases intestinal and gland activity. It essentially takes over when one relaxes from an exciting ordeal.
ACTION POTENTIAL
During an Action Potential, a part of the neural membrane/ molecular gates open up to allow positively charged ions inside the cell and negative ones out.
With sodium being a positive ion, channels open up and positive sodium cells surge into the cell in preparation for an electrical signal being sent down the axon once a threshold has been reached.