Answer:
Nitrogen is present in the atmosphere in a molecule form about 78 percent. This nitrogen comes to the earth with the water through rainfall. Some nitrogen fix by beneficial microorganisms such as Cyanobacteria and Azotobactor which are present in the roots of higher plants. These microorganisms convert nitrogen molecule into nitrates and used by the plants. There are some other microorganisms which again convert nitrate into nitrogen molecules, called denitrifying bacteria and nitrogen molecule goes to the atmosphere again and complete the cycle.
<span>Fish that can tolerate a wide range of salinity at some phase in their life-cycle are called euryhaline species. These fish, which include salmon, eels, red drum, striped bass and flounder, can live or survive in wide ranges of salinity, varying from fresh to brackish to marine waters.</span>
