Pedro is a phd student performing a research on aerobic organisms. he has to understand how aerobic organisms survive under water. which topic should pedro read up on to understand this phenomenon?
ocean currents
upwelling
tides
downwelling

Downwelling  topic should be read by Pedro to understand the phenomenon.

Explanation:

The sinking and accumulation of high density material beneath the material of low density is the process of Downwelling. One such example is of- the saline water lies beneath the freshwater. It takes place in the oceanic anti-cyclonic areas where surface convergence is created.

It causes ventilation in oceans and helps in facilitating aerobic respiration in different organisms by bringing surface oxygen dissolved in water. This condition is the reason behind the survival of aerobic organism under water.  

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