Final answer:
A check valve is a one-way valve designed to prevent backflow, similar in function to valves in the cardiovascular system. Manometers, which measure pressure, come in closed-ended and open-ended varieties.
Therefore, the correct answer is: option "One-way".
Step-by-step explanation:
The check valve is commonly used in various systems, including the valve in the cardiovascular system, to ensure that fluid (such as blood) flows in only one direction and does not backflow.
Similar to a one-way valve in function, a manometer is a device used to measure pressure. Manometers come in two main types: closed-ended manometers and open-ended manometers.
Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave. In a closed-ended manometer, one end is closed with a vacuum, and the pressure measured is the difference in mercury column heights.
For an open-ended manometer, one end is open to the atmosphere, and it measures the pressure difference between the atmospheric pressure and the contained gas pressure.