Address the need to get oxygen to the muscles and get rid of co2, as well as how the muscles cells get the energy needed to continue contracting.

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

Which two factors contributed to creating a global culture? the creation of the united nations improvement in telecommunications health issues such as the ebola virus increased opportunities for global travel

Eutrophication caused by human nutrient pollution.