You are presented with the question "What prolongs the storage life of food in space?" and the following answer choices: 
- hydrogen and oxygen
 - preservatives
 - Dehydration
 - heating liquids
 - Fuel cells
 - heat energy
 - hard outer covering
 - layers of fat

Now knowing that astronauts require preserved food for extended flights and preservatives are added to extend the shelf life, choose the best answer.


 

  preservatives       