As long as the equipment used to slice the onions was clean and sanitary, sliced onions are perfectly fine to eat. Store sliced onions in the refrigerator.
This is a difficult question to answer, sliced ham should not be soft and mushy, so it is perhaps better not to eat it. However if the ham has been cooked properly and stored in a cool place since being cooked (and if it is from a shop, is still within is use by date) it should be OK to eat. It may be that it had too much water in it when it was packed. On balance however if food does not look OK, is out of date, has not been stored at the correct temperature and certainly if it smells bad - it is safer not to eat it.
No. They are starting to spoil.
It should be ok to eat. When cooking watch out for spoil smell to make sure it is ok.
no if they have been sitting there for more than 2 days you really should not eat them.
Yes. Baboons have been known to attack and eat small children.
Is it ok to eat pomegranate
Yes but don't feed them burgers if it has onion in it because that can upset their stomachs, not even onion flakes. it still upsets the digestive system. Actually onions cause hemolytic anemia in dogs which really why you should not feed them onions. Does nothing to the digestive tract.
If it has not been sitting out all night on the counter a room temp. then it would be ok to eat. But if it has been sitting out al night then you shouldn't eat it.
no you should never eat meat that has been left out under any circumstances
Yes. It should be fine as long as it has not been left out in extreme temperatures, uncovered.
the worst are cooked bones, chocolate, grapes and raisins, and nuts. (although peanut butter is OK)
If you are an amammal, more than likely there will be no reaction. However this has not been tested on Aliens yet