I have kept an open #10 can of Signature brand sausage gravy in the refrigerator, uncovered, for a week. I havent had any food poisoning.
no
Flies and bees will both sit on uncovered food. Food should always be covered especially when outside in the elements.
when food is uncovered for a long time micro organisms adapt the food which causes damage to our health. in covered food micro organisms cannot occupy it
it is not healthy
Assuming you mean "uncovered in the refrigerator, what happens is that they dry out - badly - and they also "pollute" each others flavors. The applesauce will taste like broccoli, etc.
Biological
what is the place where food is kept
It is not good to eat uncovered food because many of the harmful microorganisms spoil the food making us fall ill
After Napoleon's men uncovered the Rosetta Stone, the Stone was shipped to Europe and (obviously) kept there.
Soup
B kept in air tight containers