1. Compare the digestive systems of a flatworm and a human. Be sure to include examples of the various structures found in the digestive systems of both organisms.
2.Name the trophic levels in an ecosystem and explain how energy moves through the trophic levels. Use the terms food chain and food web in the discussion.
3. Describe two of the following environmental issues that confront modern society: global warming, air pollution, acid rain, and hazardous waste. Explain how the issues are problems for society and how scientific studies can inform people concerned with the issues.