Who made the first scientific discovery of an element?

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains

Ineed ! i have no clue how to do this problem.

Insoluble sulfide compounds are generally black in color. which of the following combinations could yield a black precipitate? check all that apply. na2s(aq)+kcl(aq) li2s(aq)+pb(no3)2(aq) pb(clo3)2(aq)+nano3(aq) agno3(aq)+kcl(aq) k2s(aq)+sn(no3)4(aq)