TASK DEFINITION: In this task, you are given a question and answer for that. The answer will fill in the blank or will complete the unfinished question. Your task is to provide an explanation based on the given question or fill-in-the-blank statement, and answer.
PROBLEM: Question: Do gas engine cars pollute more or less than electric engine cars? 
 Answer: more

SOLUTION: Plug-in hybrids run for a longer time on electricity and so are less polluting than regular hybrids.

PROBLEM: Question: Ray was traveling in rocket leaving orbit. He keeps the empty fuel containers on board so the ship can fly 
 Answer: lower

SOLUTION: By using multiple stages, empty fuel containers could drop away. This reduced the mass of the rocket so that it could fly higher.

PROBLEM: Question: John was looking at the materials being manipulated. He saw that the more it was compressed the force 
 Answer: Decreased

SOLUTION:
The elastic force increases the more the material is stretched or compressed.