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.
Harmful, because there would not be enough resources
Greenhouse is due to excess of CO2 , Methane gas !! It has both benefits and demerits !!
They do this real fancy thing called breathing. There's a couple other organisms that do this too, but none compare to the frog
