When we chew what is saliva produced by?

Saliva is produced by enzymes. Enzymes helps food break down while we chew.

Saliva. ... Produced in salivary glands, saliva is 98% water, but it contains many important substances, including electrolytes, mucus, antibacterial compounds and various enzymes. The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily.

explanation:

i think option no d is the correct answer

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.