It can be known from the passage that increase in the salinity of ocean water is caused by______.

A．Various factors combine to cause variations in the salinity of water.
B．As a result of the formation of ocean ice water salinity decreases.
C．The salinity of the water near the bottom of the oceans is relatively high.
D．in coastal areas the ocean is diluted by rivers.

A．Very high expectations from life make the younger generations more prone to depression.
B．A depressed person feels sad and dejected.
C．People need not attempt to hide their depression because it's not a shameful thing.
D．Depression is hereditary.