Oxygen - It is very important for all living to survive 'cause without it, cellular respiration can't take place....
Glucose - It is the simple food, it provides energy to the whole ecosystem, so that they can survive.
Without either of them, life is not possible!!!!!
Through the process of phagocytosis
No any of the organelle which is bounded by membranes.
Upwelling is important to mix the nutrients that are present deep inside the water.Updewelling is a phenomenon in which the deeper water rises and gets mixed to the surface water to promote the growth of phytoplanktons and seaweeds as the water that is present deep inside is rich in nutrients.These phytoplanktons serve as as source of energy for large fishes and other aquatic animals. As these large animals are higher in population and are an important part of food chain and they also provide food to different marine mammals ,sea birds.The deep water infuses with costal water so to serve as a fuel for high productivity of marine ecosystem.