Explain counter-current flow in gills, its advantages, and give examples in humans and adaptations in aquatic plants for gas exchange.

Fondo, let's knock this out. a) i) The type of flow shown is counter-current flow. ii) The advantage of counter-current flow is that it maintains a steep concentration gradient for oxygen diffusion across the entire length of the gill plate. This maximizes the efficiency of oxygen transfer from the water to the blood, allowing for a much higher percentage of oxygen to be extracted compared to a co-current system. b) Two organs in humans that display a similar type of flow are: • Kidneys (specifically in the loop of Henle for water reabsorption) • Placenta (for exchange of gases, nutrients, and waste products between mother and fetus) c) Two ways in which floating leaves of aquatic plants are adapted to gaseous exchange are: • They have stomata located primarily on their upper surface, allowing direct access to atmospheric air for gas exchange, as the lower surface is in contact with water. • They possess large air spaces (aerenchyma) within their leaves and petioles, which provide buoyancy and facilitate the diffusion of gases throughout the plant. Send me the next one 📸