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Correct Answer is: (a) Bays

These are two cold currents in the South Atlantic circuit.

1. Baltic sea is a brackish mediterranean sea located between Central and Northern Europe. 

2. The Baltic sea’s salinity is much lower than that of ocean water. 

3. Baltic is a small sea on a global scale. 

4. The causes for the low salinity of the Baltic sea are 

a) The abundant fresh water run off from the surrounding land. 

b) The shallowness of the sea. 

c) The flow of fresh water into the sea from approximately two hundred rivers and the introduction of salt from the south builds up a gradient of salinity in the Baltic sea. 

d) The Baltic sea is only connected to the world’s oceans by the narrow and shallow waters of the Sound and Belt-sea.

e) This limits the exchange of water with the North sea and means that the same water remains in the Baltic for a lot of years. 

For all the above reasons the salinity of the Baltic sea is less than that of the salinity of the oceans.

The salinity at the equator is less even though it experiences high temperature, because of heavy rainfall and high relative humidity as precipitation adds good amount of fresh water to ocean water.

1. As the rain erodes the rock acids in the rain water break down the rock.

2. Ions (or) electrically charged atomic particles are created.

3. These ions are carried away in runoff to streams and rivers and ultimately to the ocean.

4. Many of the dissolved ions are used by organisms in the ocean are removed from the water.

5. Others are left for long periods time where their concentrations increased overtime.

6. Sodium and chloride are the most prevalent ions in Sea water, (about 90%) making sea water salty as it is salty

Conservation of ocean means rational uses of ocean resources. So that a harmony between man’s ocean resource requirements and their availability could be maintained. The rational uses of ocean resources by the present generation and the preservation of ocean resources for the future generations, is known as conservation of ocean. It also means the protection of oceans and ocean resources against pollution caused by dumping of oceans and of industrial, agricultural and municipal wastes into oceans by man, oil spill from oil tankers, and nuclear explosions in sea and oceans.

Need for conservation of Oceans: There is a need for conservation of oceans due to the following reasons:

• If oceans are not conserved, all the living organism in the oceans either die or become unsuitable for human consumption. 
• Oceans are the storehouse of pearls, corals and sponges. These resources have to be conserved. 
• Oceans have oil and natural gas reserves. These reserves have to be conserved. 
• Oceans are rich in minerals. These mineral resources have to be rationally exploited. 
• Oceans allow the growth of innumerable species of plants. These plants have to be conserved. 
• Oceans are the breeding centers of marine fisheries. Thousands of fishes are found in oceans. The marine fishery resources should be exploited rationally. 
• Literacy and education programmes on marine features must be initiated and promoted. 
• Proper law to be enacted to save sea and ocean.

World wise awareness programme must be arranged to show the pro and cons of the marine pollution etc. 

• Mozambique current 
• Madagascar current 
• West Australian cold current 
• West wind drift.

River water contains 2 % of sodium chloride.

(b) Continental shelf

About 80 % they all together constitutes. 

Answer-: option D

77.8% of Sodium Chloride or common salt constitutes in sea water 

A) Salinity of ocean

The average salinity of the oceans is 35%

• Lake Van is fed by streams descending from surrounding mountains. 
• It has no outlet, as outlet once present was closed by volcanic eruption. 
• Water here is with a pH value of 9.7 – 9.8. 
• It is situated at an altitude of 5380 ft. 
• But because of its salinity of 330%, (oceans have 35% salinity) it is free from freezing.

There are two types of ocean currents e.g., warm and cold currents. The current which flows from warm tropical region to cooler temperate and polar region is called warm current and the current flowing from polar areas towards temperate and equational regions is called cold current, e.g. Gulf stream is a warm current and Labrador current is called cold current.

Elnino; Lanino: These are the effects caused by the changes in temperature in the Pacific Ocean.

The salinity of the Dead sea is 238 %

The temperature at the foot of the ocean is 1.8°C

(A) Lake Van

(B) – 2°C to 29°C

97.25 % of water is saline ocean waters.

Agulhas current found in South Africa.

B) Continental shelf

A) The Pacific ocean

The direction of the currents is clockwise in the northern hemisphere and anti-clockwise n the southern hemisphere.

C) Warm Currents flow towards the poles and Cold Currents towards Equator

The movement of sea surface water dragged with the prevailing winds is known as ‘drift’.

Oyash.io and Okhotsk current are the cold currents of North Pacific Ocean.

B) The Atlantic ocean

B) The Atlantic

(D) Atlantic

Warm and cold currents.

The currents which flow from the polar areas carried cold water. These are known ass cold currents.

Each day a tide is delayed by 26 minutes because the moon also rotates on its axis (west to east) while revolving round the earth. Since the earth rotates from west to east, the tide centre shifts westward. When the tide centre completes one round, the moon’s position is ahead of the tide centre by that time. The moon also revolves round the earth, with the result, the tide centre takes another 52 minutes to come under the moon. Thus, a particular tide centre takes 24 hours 52 minutes to come under the moon but by that time there is another tide at the opposite side of the referred tide centre and this happens after 12 hours 26 minutes.

Due to the cooling effect of Labrador current keeps these coasts comparatively cold.

D) Pacific Ocean

Warm currents of Gulf Stream has made the climate of eastern North America and Western Europe mild and pleasant for ideal industrial life and developed oceanic routes for trade. In the same way warm Kurosio current has made Japan a progressive country by leading in fishing occupation supporting the economy of Japan, Apart from this violent storms also follow the meeting places of warm and cold currents, e.g., Hurricanes in America and typhoons in China and Japan.

The currents originating in the tropical region have warm waters called warm currents’.

The length, width and areas of oceans is measured by means of nautical miles. One nautical mile measures a length of 6080 feet.

The Great Barrier Reef: 

The Great Barrier reef is the world’s largest coral reef system composed of 2,900 individual reefs and 900 islands stretching for about 2,000 kilometres. It covers an area of about 3,50,000 km. The reef is located in the Coral sea, off the coast of Queensland, Australia. The Great Barrier Reef can be seen from the outer space. This sprawling coral reef system is one of the most biologically diverse places on the planet. Coral reefs are built by billions of tiny organisms, known as Coral polyps. CNN labelled it as one of the seven natural wonders of the world.

(D) Gulf stream

1) D 

2) E 

3) C 

4) A 

5) B

Hydrosphere, the third sphere of Earth is a collection of all forms of water on the earth.

Pacific Ocean, Atlantic ocean Indian Ocean, Antarctic Ocean and arctic oceans. 

(B) Gulf stream

The total water mass on the earth’s surface is called hydrosphere.

East coast of Australia.

D) West Australian

Southern hemisphere is called water hemisphere.

Indian Ocean.

The scientific study of water bodies (Sea, Oceans) is called ‘Oceanography’.