Which of the following keeps food viable for extended flights? 
evaporation microwaving boiling freeze drying layers of fat deep frying mechanical Dehydration
A B C D E F G H
Freeze-drying Freeze drying is a method of preserving materials.
Freeze drying food keeps it viable for extended flights. 
Which of the following keeps food viable for extended flights?  (A) evaporation (B) microwaving (C) boiling (D) freeze drying (E) layers of fat (F) deep frying (G) mechanical (H) Dehydration