Final answer:
The uncooked chicken legs should be stored on the bottom shelf to prevent juices from contaminating other foods. Cooked leftovers are unsafe after two hours at room temperature, and melons should be washed before cutting. Jams and dried meats often do not require refrigeration due to their inhospitable environments for bacteria.
Step-by-step explanation:
The item that should be stored on the bottom shelf of a refrigerator is an uncooked chicken legs due to the potential for raw poultry to drip and contaminate other foods.
In a safe food storage hierarchy, raw meat and poultry should always be kept at the bottom of the fridge to avoid any juices -- which may contain bacteria -- from contaminating other foods stored below them. Items like hard-boiled eggs, whole salmon, and an uncooked pork roast should be stored above raw chicken to prevent cross-contamination.
Regarding the safety of cooked leftovers, if they have been stored at room temperature for more than two hours, they are not safe to eat even if heated, due to the potential growth of bacteria.
As for melons, it's false to assume there's no need to wash them; the rind should be washed to prevent bacteria from transferring to the flesh when cutting. Foodborne diseases can indeed cause serious health issues.
High sugar concentration in jams and the curing process in dried meats create environments that are inhospitable to bacterial growth, which is why they often do not require refrigeration to prevent spoilage.