In the oceans,the environment is perpetually dark at depths of:

Given below are five statements.
$A.$ Organisms living in oceans,lakes,and rivers also face water-related problems.
$B.$ Euryhaline can tolerate a wide range of salinities.
$C.$ Stenohaline are restricted to a narrow range of salinities.
$D.$ Many freshwater animals cannot live for long in sea water because of the osmotic problems they would face.
$E.$ The salt concentration (measured as salinity in parts per thousand) is less than $5$ in inland waters,$30-35$ in the sea,and $>100$ in some hypersaline lagoons.

Does light factor affect the distribution of organisms? Write a brief note giving suitable examples of either plants or animals.

The abyssal zone of oceans is characterized by:

The salinity is ............ in hypersaline lagoons.

Which of the following is the most ecologically relevant environmental factor?