Final answer:
Mechanical digestion is the physical process of breaking down food through actions like chewing, while the five primary tastes that humans can distinguish are sweet, sour, bitter, salty, and umami.
Step-by-step explanation:
One type of digestion is mechanical digestion, which involves physical processes like the chewing of food in the mouth and the churning of food in the stomach. These actions break down food into smaller pieces, increasing the surface area for enzymes to work on during chemical digestion. As for the basic tastes, humans can distinguish five primary tastes: sweet, sour, bitter, salty, and umami. Sweet taste is stimulated by sugars, sour by acids, bitter by alkaloids, salty by ions like sodium and chloride, and umami, which means 'delicious taste' in Japanese, is triggered by glutamate and often associated with savory flavors.
Each of the five basic tastes has its own specialized receptor type on taste cells located within taste buds on the tongue's papillae. The taste cells activate when tastants, the molecules responsible for taste, are dissolved in saliva and bind to their appropriate receptors, sending signals to the brain that identify the taste qualities of the food we consume.