Answer:
The valves' main job is to keep the blood moving in one direction – back up towards the heart. When the valve is open, blood freely flows upward towards the heart and when the valves are closed, blood cannot flow back
Answer:
herbivore: koala, etc
Carnivore: tigers, lions, hyenas
Explanation:
ingestion, propulsion, mechanical or physical digestion, chemical digestion, absorption, and defecation. The first of these processes, ingestion, refers to the entry of food into the alimentary canal through the mouth.
2. A. Rubber is a conductor and transfers electricity from the wire.
3. B. Changing tides.
4. B. The fossils may have been moved by man, animals, or Earth's constructive and destructive processes.
5. A. They are produced by drought.
6. C. Stores heredity information.
7. D. Magnets have a set strength , while the strength of an electromagnet can be adjusted.
8. A. Temporary dam.
9. B. Invertebrates.
10. C. Human feces.
11. No answer.
12. A. Gas.
13. C. Increase the number of coils of copper he puts around the nail.
14. A. Sam is correct. It is not a physical change.
15. C. Landslides.
