Where is a continental shelf usually found
this is science

May someone me with these science questions

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)

One student said that the investigation was not valid (a fair test). write a plan for the investigation that includes improvements to the method and apparatus