Why was the "commons" not a problem in the
past?

If it releases 5 tons a day and there are 7 days a take that answer and multiply by 5 percent (0.05) to find the amount released in one week. leave a comment if you need more .

C. definite shape, definite volume. that is a solid.

If your on odysseyware i believe the answer would be c. 

Bromine has atomic number  35  which means there are  35 protons  and  44  neutrons to give a total of 79 nucleons. the fact that it's a positive ion means that it has lost an electron; so there'll be  34 electrons.