Which statements describe the importance of the nitrogen cycle to living things? Check all that apply. It provides a source of water. It helps cells make proteins. It provides a form of usable nitrogen. It removes carbon dioxide from the atmosphere. It destroys harmful bacteria. It helps cells make glucose

Why should the united state be concerned about air pollution in china?

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?

Humans are believed to have evolved in coastal regions in east africa. the region had an abundant supply of fish for early humanoids to eat. when scientists analyze the fads gene they see an interesting pattern. people whose families have lived in this area of east africa for generation show a high level of diversity in alleles for the fads gene. conversely, people whose families had migrated inland a moderate distance from sources of fish showed a much lower diversity for fads gene alleles. additionally, the fads alleles found in people whose family has lived inland for generation are almost all gene alleles which produce fads proteins with a high level of function and activity. how do anthropologists explain this?