Nerve cells communicate by sending an electrical signal through an axon, from this molecules get released into the synapse this then binds itself onto receptor sites. With ion-linked channel receptors, the ligands get binded to a protein. The ion channels are then opened and the proccess gets repeated. Does that help?
I think the correct answer from the choices listed above is option C. The function that is both performed by goblet cells and lacrimal glands is protection. They produce mucus in order to protect mucous membranes. Hope this answers the question.
