Originally Posted by esprit

There is no limit on the size. I am not sure about the Milli Vanilli question, but I suspect the reason the explanation was abbreviated is the same reason the Monkees explanation was cut short. I also assume that you are referring to the Monkees question when you say that a couple of them were shortened.

Your explanation:
"The Monkees" were a pop-rock quartet created and based in Los Angeles in 1965 for an NBC American television series of the same name.

Wikipedia:
The Monkees were a pop-rock quartet created and based in Los Angeles in 1965 for an NBC American television series of the same name.

Your explanation:
The show, which ran from 1966 to 1968. It ultimately helped make them one of the most popular music acts of the decade.

Wikipedia:
The show, which ran from 1966 to 1968, helped make them one of the most popular music acts of the decade

The editor had to make a decision, and he decided to shorten the explanation removing certain sentences.

In the case of the Black Panther Party quiz you cited, the explanation could not have been modified by the author and is not considered plagiarism. Just like it wouldn't be plagiarism to cite The Constitution.

I hope this makes sense.

Regards,
esprit