Which changing external condition triggers the salivary glands?

The sense of smell. For example, when we smell a strawberry pie, our mouth salivates.

Hey there, for asking a question here.  the postovulatory phase  of the ovarian cycle leaves the leftover follicle, from which the ovum was released, develop into the corpus luteum.answer: letter a  ✅hope that ! ★ if you have further questions about this question or need more , feel free to comment below or post another question and send the link to me. -unicornfudge aka qamar