Trilobites are index fossils because they

which elements do geologists measure to determine the age of an organism’s remains? check all that apply.

carbon-14

nitrogen

carbon-12

radiative zone

explanation    

radiative zone is the layer of the sun which energy is transferred away from the core by radiation. although, the core is the only part of the sun that produces an appreciable amount of heat through fusion. in fact, 99% of the energy produced by the sun takes place within 24% of the sun's radius.