I believe it’s bacteria but your choice
If it is already balanced because the compounds aluminum(Al) and oxygen(O) have the same number of atoms
She needs to know the amount of slices every person is going to eat
If the level of acid in a lake increased, then the number of fish that live there will be decreased because highly acidic lakes will not have enough food for the fish to survive. Acidic level increases , then availability of food for fish decreases as some food will be contaminated so if the fish won't got enough food for their survival then their number of fish decreases.
