Dihydroxyphenylalanine (DOPA) is the precursor for dopamine. Of the options, only dopamine, epinephrine, and norepinephrine are released upon nerve firing.

NETs are used to remove norepinephrine from the synaptic cleft. Tryptophan hydroxylase and amino acid decarboxylase are part of the serotonin synthesis pathway. VMA is a breakdown product of norepinephrine.

Epinephrine binds to the alpha-adrenergic receptors of the beta cells. Via intracellular signaling cascades beginning with the G protein-coupled receptor, adenylyl cyclase is activated, converting ATP to cAMP. Epinephrine is released from the adrenal medulla, not the adrenal cortex. It is also elevated when insulin is low, not high.

The receptors at work in the retina are photoreceptors, which means that they are stimulated by incoming photons. Unlike many other biochemical signaling cascades that take place in the body, stimulation of these receptors actually cause cell hyperpolarization rather than depolarization. The signal is then transmitted to the brain where the information is translated into all the associated neurological effectors that carry out vision.

The neurotransmitter norepinephrine is synthesized from tyrosine by a series of reactions. In this pathway, tyrosine is converted to dihydroxyphenalanine (DOPA) by tyrosine hydroxylase. DOPA is converted to dopamine by DOPA decarboxylase. Dopamine is the direct precursor of norepinephrineand is converted to it by dopamine beta hydroxylase. Epinephrine is converted from norepinephrine by phenylethanolamine N-methyltransferase.

Phentolamine is an alpha-antagonist. Propranolol is an beta-agonist. Epinephrine/adrenaline is the methylated form of norepinephrine/noradrenaline.

Insulin is secreted in response to high blood glucose levels, which increases cell uptake of glucose. Glycogen has the opposite effect - it stimulates glycogenolysis and lipolysis to release glucose into the bloodstream during times of fasting/starvation.

Elevated arginine leads to an increase in secretion of insulin, not decreased. GIP, CCK and closing of the voltage gated potassium channels lead to an increase in secretion of insulin. 

Ketone bodies, which include acetoacetate, beta-hydroxybutyrate, and acetone, are produced by the liver in the fasting state by beta-oxidation of fatty acids. They are then released into the blood stream, where they can be used as alternative energy sources for other organs, such as muscle, kidney, and brain. Apoprotein B is one of the proteins that hold lipoproteins together. Beta-carotene is a vitamin with antioxidant properties. 

Epinephrine first binds to an adrenergic receptor. The activated receptor works via a G protein, and so GDP is exchanged for GTP and the protein is activated. This then causes activation of adenylate cyclase and subsequent conversion of ATP to cAMP. cAMP acts upon protein kinase A and several other effector molecules. Diacylglycerol and IP3 are second messengers that are uninvolved in this process.