Uestion 12 which of the following best describes the difference between a source and a mouth? a source is where a river or stream originates, and a mouth is where it empties into another body of water. a source is where a river or stream empties into another body of water, and a mouth is where it originates. a source is partially surrounded by land, and a mouth is completely surrounded by land. a source is completely surrounded by land, and a mouth is partially surrounded by lan