It is not good to eat uncovered food because many of the harmful microorganisms spoil the food making us fall ill
An uncovered will will eventually become polluted with dead animals and insects that fall into it. It is also dangerous to humans and domestic animals. Cover it.
Yes fungi can be found in canned food that is left open for sometime.
You should use your left hand to open the left-hand door.
Yes
open
open uncovered building
Open salt is a uncovered kitchenware which contain salt.
honey is only that does not spoil when left open
To open the left-hand door, you should push it to the right.
yes it will rot
Foods stay frozen in the uncovered freezers at the store because cold air drops and stays in the freezer. There is a certain level, though, above which the frozen foods should not be stacked - otherwise they will thaw out.
If there is food in it - yes. If no food, then it doesn't need to be left on - but you might want to prop open the door to allow air circulation to help prevent the growth of mold and mildew.