1. what is the basic unit of organization of all living things? 2. what is the difference between an organ and an organ system? 3. for your organ system, describe how the system works at the organ level. 4. for your organ system, describe how the system works at the tissue level. 5. describe what would happen if an organ in your specific organ system stopped working. level 1: organ system  level 2: organ  level 3: tissues of the system  

Which of the following statements is a scientific claim? a. the early solar system had large amounts of water; so, the oldest objects in the solar system should also be abundant in water. b. earth is shaped like a sphere even if not all of the scientific observations related to its shape support this idea. c. the mass of the universe is much greater than current models predict; it is not possible to explain this inconsistency. d. planet earth is abundant in water, but there is no way to scientifically determine from where earth's water originated.