Answer:

Explanation:
When activated, the receptor most likely prompting the production of saliva is the taste receptor. When food enters the mouth, the salivary glands produce the saliva upon the sensation of taste.
Answer: spectroscopy
Spectroscopy is the separation of the light in the different wavelengths and spectrophotometry measures the intensities of the different components of the light to get the composition of substances.
Answer:
Friction is when a force is applied or done by weight dragging onto something.
Explanation:
Gravity is when an object is getting pulled toward the center of what is attracting it. And applied force is when someone/sommething is applying force.