As used in paragraph 8, the word runaway most nearly means
A. uncontrollable
B. unexplainable
C. unpredictable
D. unbelievable
Where it was used in the text: This greenhouse effect was especially bad on Venus. While planets such as Earth have a little bit of a greenhouse effect (this is what keeps Earth warm and able to sustain life, instead of being a cold place such as Mars or Jupiter), Venus had a runaway greenhouse effect.
I think that this is the most accurate response because the word runaway is often used in the terms of something that can't be controlled. For example: A runaway ball. A runaway greenhouse effect meant that the amount of heat on venus was uncontrollable and therefore it is not suitable for humans, animals, or plants to live on.
