variation. divergence among individual animals of a group. The differences in the morphology or function of an organ or organism, are small enough to stay within the variability of the type organism or organ.
According to the Food and Drug Administration, your fridge should be set at or below 40 F (4 C). Your freezer should be set at 0 F (-18 C). Food stored in the freezer at 0 F will remain safe indefinitely, although the quality will decrease the longer the food is in the freezer. Freezing does not change a food's nutritional value.
A freezer thermometer is the best way to know exactly temp your food is being stored at. Amazon carries some great options including this one. The ideal freezer temperature is 0 Fahrenheit (-18 Celsius) for all food storage. And -10 Fahrenheit (-23 Celsius) is recommended to quickly freeze food. For example, if I am planning to fill the freezer after a day of shopping or freezer cooking I'll turn the temp to -10. The next day, when everything is frozen solid, I move the temp back to 0.