Black holes themselves can not be seen, nor do they leave trails (since emptiness does not have to be caused by a black hole), but there is evidence for black holes: scientists can see the effects of their gravity on nearby stars. The answer is B.
Answer:
Personally, I would make some changes to the school systems. I would increase the national payment to schools, and try to make them a better overall place. I would also make a group of around 4 or 5 people to make decisions. There would be no president, just that group. Also I would let some jobs available to kids 13 or up. They would have to be proven responsible though.
Explanation:
I hope this helps, i kinda just spat random things out there but i tried, hope this is enough :D
