Organisms living in the deep bathypelagic and abyssopelagic zones require oxygen for respiration. what process brings oxygen from the epipelagic zone to deeper oceanic zones? crosscurrents downwelling in polar regions upwelling from equatorial to polar regions diffusion

The correct answer is upwelling from equatorial to Polar Regions results in bringing oxygen from the epipelagic zone to deeper oceanic zones.  

It is a process in which the wind mediated motion of nutrient-rich, dense, and cooler water is moved towards the surface substituting the nutrient depleted and warmer surface water. The epipelagic zone refers to the upper layer of the ocean, which is abundant in oxygen and gets the majority of the sunlight for the procedure of photosynthesis. The upwelling of water from the equatorial to the polar region brings oxygen.  

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products