Quick Quiz: Nouns Score: Change category, Flip order Reset Correct! Noun: carbonic acid Your choice? a weak acid known only in solution; formed when carbon dioxide combines with water a cluster of malignant cells that has not yet invaded the deeper epithelial tissue or spread to other parts of the body the amount of blood pumped out by the ventricles in a given period of time the valve between the distal end of the esophagus and the stomach; the physiological sphincter at the esophagogastric junction