An estuary is an area where a freshwater river or stream meets the ocean. In estuaries, The salty ocean mixes with a fresh water river, resulting in brackish water. Brackish water is someone salty, but not as salty as the ocean. An estuary may also be called a bay, lagoon, sound, or slough.
The answer should be both
The cell membrane is semi-permeable, kind of like a filter to let some molecules in and keep larger molecules out
