Controls at railroad crossings include: a. crossing gates b. flashing green lightsc. crossing guardsd. sirens

To me, the Answer to this problem is A. Crossing Gates.

it would take 95 years for that supernova to be visible on earth, so the year would be about 2113. i hope i did my calculation right.

from the word list given, the most suitable words that relate to the reason information were written would be:  

objectivity: lack of bias, judgment, or prejudice

accuracy: free of mistakes, to be correct

authority: the ability to tell people what to do or believe in

content: to be satisfied  

it can be said that the author made the article to present objectivity, to provide accurate information, to be the authority in the subject that he or she writes, and to be satisfied of the information quality given out.