Experiment1: heart valves and pumps

Data Tables
Table 2: Experimental Observations
Post-Lab Questions
1. What happened when you pressed on the balloon stretched over the jar? What does this result represent? 
2. What structure in this experiment mimics a heart valve?
3. How did the valve influence the experimental results? If possible, indicate the difference in water displaced (in mL) with the valve versus without the valve. Does the valve enhance water flow? Why?
4. What other organs or body systems incorporate valves? How are they used?