Question

B.
Prepare a Summary of the given paragraph in 4-5 sentences. Begin with a
suitable title to the summary.
(3 Marks)
Salt in the ocean comes from two sources: runoff from the land and openings in the
seafloor. Rocks on land are the major source of salts dissolved in seawater.
Rainwater that falls on land is slightly acidic, so it erodes rocks. This releases an atom
or a group of atoms that are carried away to streams and rivers that eventually feed
into the ocean. Another source of salts in the ocean is hydrothermal fluids, which
come from vents or cracks in the seafloor. Ocean water seeps into cracks in the
seafloor and is heated by magma from the Earth's core.
The heat causes a series of chemical reactions. The water tends to lose oxygen,
magnesium, and sulfates, and pick up metals such as iron, zinc, and copper from
surrounding rocks. The heated water is released through vents in the seafloor,
carrying the metals with it. Some ocean salts come from underwater volcanic
eruptions, which directly release minerals into the ocean. The
concentration of salt in
seawater (salinity) varies with temperature, evaporation, and precipitation. Salinity is
generally low at the equator and at the poles, and high at mid-latitudes. The average
salinity is about 3.5 percent of the weight of seawater, which comes from the
dissolved salts.​

Answer 1

Title:

Ocean Salinity

Summary:

The salt in the ocean originates from the runoff from the land and the openings in the sea floor.

The major source of salts are rocks and another important source are the hydrothermal fluids. Some salts may also come from underwater volcanic eruptions which includes evolution of heat from the magma of the earth to a number of chemical reactions leading to the formation of salts and minerals. The salinity of oceans constantly changes with a change in temperature, evaporation rate and precipitation and it is generally high at the mid-latitudes but low at the equator and at the poles.