In a sample of double-stranded DNA, 12% of the nitrogenous bases are guanine (G). What percentage of the nitrogenous bases in the sample are cytosine (C)? Explain how you know

Found evidence that the continents were joined together at one time.

Read the following scenario to answer the following question. in some zoos, rare crosses between a male lion and a female tiger have produced hybrid offspring called "ligers." male ligers are sterile but some female ligers are fertile. in the wild, lion and tiger ranges do not naturally overlap, making such a cross unlikely. furthermore, the solitary behavior of tigers and the social organizations of lions create behavioral differences. applying the biological species concept, the sterility of ligers reveals that a. lions are probably a subspecies of tigers b. tigers and lions are the same species c. a new species called "ligers" is forming d. tigers and lions are separate species

What two fields of study provide the core information that is used to classify organisms?