Atypical ecosystem like the one pictured here might have 200,000 caterpillars, 10,000 frogs, 500 snakes, and 35 owls. why do you think there are fewer and fewer organisms at each level of the food chain?

Which of the following types of pollution is most responsible for large numbers of deaths worldwide because of unsafe drinking water? (a) nutrient pollution (b) thermal pollution (c) pathogen pollution (d) sediment pollution