A. Coral reef life needs saltwater to survive, therefore it is SALTWATER.
B. Estuaries are partially enclosed water bodies in the coast, where freshwater from rivers/stream mixes with salt water from the ocean, therefore it is BOTH.
C. Rivers and streams have populations that are adapted for freshwater, so it is FRESHWATER.
D. Open oceans have high salinity, therefore it is SALTWATER
E. Lakes can be freshwater or saltwater, and ponds are usually freshwater, with the rare exception of ponds that are on natural salty areas or filled up by tidal flow. Therefore, it is BOTH.
F. Wetlands are areas of land that is covered with water for a certain period. There are freshwater and saltwater wetlands, therefore it is BOTH.