Final answer:
Lake Ontario is drained by the St. Lawrence River, the Genesee River, and the Niagara River.
Step-by-step explanation:
Lake Ontario is drained by several rivers, including the St. Lawrence River, the Genesee River, and the Niagara River. The St. Lawrence River is the primary outlet for Lake Ontario, flowing northeast out of the lake and eventually emptying into the Atlantic Ocean. The Genesee River, located in New York state, also drains into Lake Ontario. Additionally, the Niagara River drains Lake Ontario at its easternmost point and flows into Lake Erie. These rivers play an important role in maintaining the water levels and overall ecosystem of Lake Ontario.