The answer is; C
Fossil fuels are the remains of an organism that lived in the past and have been preserved or their impression has been preserved. Fossils are studied to identify the difference (genetic and phenotypic) between past and future related organism and are carbon dated to determine the time in which the organisms existed. The study of fossils is called paleontology.
The answer is D. Old stone tools with be more classified as an ancient artifact where the others would be classified as fossils.
The answer to your question would be (<span>barter)</span>
Yes. Air can be separated through fractional distillation. The air must be cooled to a liquid first. Considering nitrogen oxygen and argon all have different boiling points, the liquid air mixture can be heated very gently and carefully in a fractionating column. Each element will eventually vaporise and they can be condensed and collected at different points up the fractionating column because they each have different boiling points.
