Your outer skin is your epidermis, so just look at your arm
i believe that it is chromosomes
A string of nucleotides that hold information is called a gene. :)
I would say D because it involves more selection but if that one is wrong it is most likely B. But I would go with D
Answer:
fossil fuels
Explanation:
oil, coal, and natural gasses once separated for a long time, form fossil fuels