Index fossils are used to determine the relative ages of rock and fossils and are also used to A) define the boundaries between geologic periods B) determine the absolute age of surrounding rock C) identify the fossil species found in rock layers D) infer evolutionary relationships between organisms

Answer A  is the answer

Explanation:

lithosphere and asthenosphere

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.