You are presented with the question "A scientist who is a space explorer requires what for extended flights?" and the following answer choices: 
- preserved food
 - salt and water.
 - hydration
 - a hydraulic system
 - useless heavy objects
 - short-lived food
 - hydrate their cells
 - perishable food

Now knowing that astronauts require preserved food for extended flights and an astronaut is a scientist who is a space explorer, choose the best answer.


 

 preserved food        