If an organism's fossil was found in the Mississippian era and a different organism fossil in the Devonian era, which organism would you say roamed the Earth first, the one in the Mississippian or the one in the Devonian? How do you know? Two part question i need the answer as soon as possible its urgent!

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.