Calculate the following to four significant figures: (a) the percent composition of ammonia, NH_3 (b) the percent composition of photographic fixer solution (“hypo”), Na_2S_2O_3(c) the percent of calcium ion in Ca_3(PO_4)_2

the solar system used to have much dust particles option no d

i think   the answer is c hope i'm right

it should have an internal chamber and two thermometers sticking out of the top. the internal chamber will also be closed off from the outside.