The salinity in salt marshes can vary throughout the day because
a.
river flow changes throughout the day
b.
the amount of salt water in a marsh depends upon ocean tides
c.
daily winds and rains result in salt and fresh water mixing
d.
salt water collects in the lowest elevations

b.  the amount of salt water in a marsh depends upon ocean tides.

Salt marsh is a biome that is located in the coastal region. It is the biome which is intermediate between land and sea water. It is dominated by the salt tolerant plants such as grasses, shrubs and herbs. It transfers nutrients to the sea water.

The salinity in salt marshes can vary throughout the day because the amount of salt water in a marsh depends upon ocean tides. The low and high tides flood over the salt marsh it will influence the salinity of water in the salt marsh region and can disturb the plant and animal life which are not tolerant to drastic salt conditions.