Which changing external condition triggers the salivary glands?

A) lack of oxygen

B) lack of water

C) disease-causing agents

D) change in temperature

The correct answer is lack of water. The salivary glands are triggered when there is lack of water. When the mouth is dry due to lack of water, the salivary gland are triggered and produce saliva to lubricate the mouth. Saliva which is secreted by the salivary gland plays a very important role in digestion.