Why is each element unique and different from other elements with respect to its chemical properties?

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)

Someone do this for me. im really stuck

Which of the following is the most likeley example of an favorable mutation a. a mutation that makes a rabbit able run faster b. a mutation that changes the rabbit's fur to bright orange c. a mutation that changes the color of the rabbit's eyes d. a mutation that gives a rabbit a third ear