26.Where is an estuary found? A. Below the top 300 meters of the sea where there is no light. B. At the top 100 meters of the sea. C. It is a small temporary pond of water. D. It is the water that forms at the mouth of a river where it meets the sea. 27.Which is incorrect about deep-sea organisms? A. Some prokaryotes extract energy from hydrogen sulfide. B. Some prokaryotes are photosynthetic there. C. Some heterotrophic organisms obtain energy from debris that falls from above. D. Some prokaryotes live symbiotically within the tissues of heterotrophs that live there. 28.All of the following are correct about oligotrophic lakes except: A. they have an abundance of minerals and organic material B. they are often deeper than eutrophic lakes C. their deep water is rich in oxygen D. they are highly susceptible to pollution from fertilizer runoff E. they are highly susceptible to detergent and sewage contamination 29.Which zone in a lake is the shallowest part? A. Profundal B. Limnetic C. Littoral D. Fundal 30.Which part of the lake contains numerous bacteria and wormlike organisms that consume dead debris? A. Profundal B. Limnetic C. Littoral D. Fundal  Â