Why do foods stay fresh longer when stored in an airtight container? a) the container stabilizes the temperature of the system b) reactions that spoil food need oxygen to occur c) the container increases the pressure on the food

Answer is: b) Reactions that spoil food need oxygen to occur.
Aerobic organism is an organism that can survive and grow in environment with oxygen (there is approximately 20% of oxygen in air).
Airtight containers do not allowed air in or out from container, so aerobic organisms cannot live in such conditions, because they cannot oxidize the food (sugars, fats).