The energy that flows through most ecosystems comes from the sun. primary producers convert a fraction of the sun's energy into chemical energy, which can be used by consumers. food webs describe how energy flows between trophic levels in an ecosystem, and a trophic pyramid represents the amount of energy available at each trophic level. part a - identifying trophic levels in a food web

chert is a sedimentary rock composed of microcrystalline or cryptocrystalline silica. with this little bit of information, you can come to the conclusion that your answer is c.  

explanation:

regents of the university of california v. bakke, 438 u.s. 265 (1978), was a landmark decision by the supreme court of the united states. it upheld affirmative action, allowing race to be one of several factors in college admission policy.