1. Blood in the gills runs in the opposite direction as the water outside the gill filaments. By running in the direction opposite the flow of water, the blood is always exposed to an area of water that has a higher level of oxygen. Oxygen moves across the membranes by diffusion. So if the gill had more oxygen than the water, the fish would lose oxygen to its surroundings. This is an example of:

Respuesta :

Answer:

Counter current  system  for oxygen exchange. This  process allow the exchange through diffusion of oxygen from higher concentration of water to lower concentration in the fish blood, from the surface of the  fish lammela,Therefore as  blood flows through the gill capillaries,oxygen at higher diffusion gradient,enters the capillaries, sustained by higher diffsuion rate of Oxygen Counter by opposite blood flow.

Explanation: