Match each number to its corresponding letter.
1. number of different organic compounds a) coal
2. major source of medicine b) 1,000,000 +
3. major problem in burning soft coal c) coke
4. residue of coal decomposition d) pollution
5. first organic compound synthesized e) urea

The organelle pictured is found in cells of and is theorized to have once been an independent organism.

Which is not a characteristic of bacteria? a. they are unicellular. b. they are prokaryotic. c. they are the smallest form of life on earth. d. they are multicellular.

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.