Everyday Science
NULL
Medium
Question
How many major gases have been used in refrigerators since their invention?
A
2
B
3
✓ Official correct answer
C
4
D
5
Community credibility
Registered members can vote for the answer they believe is correct today and explain why. If the facts change after an election or news event, suggest a new option so others can vote it up.
A
2
No member explanations yet for this option.
B
3
No member explanations yet for this option.
C
4
No member explanations yet for this option.
D
5
No member explanations yet for this option.
Explanation
According to the keyed exam answer, three major gases have been used.
Editor note: oversimplified history; options left unchanged.
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