B; Seawater mixes with freshwater so the water has intermediate salinity
Explanation:
In an estuary, seawater mixes with freshwater so the water has intermediate salinity. Estuaries are usually located in transitional environments. 
- Estuary is the wide part of a river where it nears the sea. 
- This is called a transitional zone. 
- Water from continental rivers usually fresh are brought in close contact with ocean water that is salty. 
- The water here is said to be brackish as it is intermediate between salt and seawater. 
- Organisms living in such terrain must be be well adapted to changing salinity. 
Learn more:
salinity and density brainly.com/question/10491444
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Answer:
Abiotic
Explanation:
Its because it includes water, sunlight, tempature and soil
 
        
             
        
        
        
Answer:
The answer is A. I took the test today.
Explanation: