In these organs in most fish, water flows the opposite direction to the blood, increasing oxygen transfer
They developed a variety of respiratory surfaces that all increase 
the surface area ... Water flows over gills in one direction while blood flows in the 
opposite... [DOC] [TLE] Ex 3 Set 1 Flashcards | Quizlet [PAR] As the blood flows in the opposite direction to the water, it always flows next to ...