Most autotrophs use water as the reducing agent, but some can use other hydrogen compounds such as hydrogen sulfide. Phototrophs (green plants and algae), a type of autotroph, convert electromagnetic energy from sunlight into chemical energy in the form of reduced carbon.
Athens is a city in and the county seat of Athens County, Ohio, United States. It is located along the Hocking River in the southeastern part of Ohio. A historic college town, Athens is home to Ohio University (26,000+ students) and is the principal city of the Athens, Ohio Micropolitan Statistical Area. The official population of Athens in the 2010 U.S. Census was 23,832.
Athens (formally known as Athens-Clarke County) is a consolidated cityâcounty in the U.S. state of Georgia, in the northeastern part of the state about an hour's drive from the global city of Atlanta, and comprising the former city of Athens proper (the county seat) and  Clarke County.