What are the similarities between an open and closed system? i will give brainliest or whatever its called!

In an open circulatory system, the cells are in direct contact with the cells in the organism. An example of this is the jellyfish. In a closed circulatory system, cells are not in direct contact with the environment.Take our own bodies for example. When we inhale oxygen fills our lungs and diffuses into our blood. When we exhale, we release waste, or carbon dioxide and other gases.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."

a physical change is being made.