Balbharti Maharashtra State Board Class 11 Geography Important Questions Chapter 6 Ocean Resources Important Questions and Answers.
Maharashtra State Board 11th Geography Important Questions Chapter 6 Ocean Resources
Complete the chain.
Question 1.
| A | B | C |
| (1) Continental Shelf | (1) Mariana Trench | (1) Methane Hydrate |
| (2) Continental Slope | (2) Mumbai High | (2) Coral Island |
| (3) Oceanic Ridges and Plateau | (3) Krishna-Godavari Basin | (3) Deepest Part |
| (4) Oceanic Trenches | (4) Aldabra | (4) Oil and Gas |
Answer:
| A | B | C |
| (1) Continental Shelf | (1) Mumbai High | (1) Oil and Gas |
| (2) Continental Slope | (2) Krishna-Godavari Basin | (2) Methane Hydrate |
| (3) Oceanic Ridges and Plateau | (3) Aldabra | (3) Coral Island |
| (4) Oceanic Trenches | (4) Mariana Trench | (4) Deepest Part |
Choose the correct option by identifying the correct correlation in the sentences.
Question 1.
The phenomenon of tides releases ………………..
(a) large amounts of energy
(b) large amounts of sediments
(c) large amounts of forces
(d) large amounts of resources
Answer:
(a) large amounts of energy
Question 2.
Desalination process ………………..
(a) is the removal of oil from sea water
(b) is the removal of petroleum from sea water
(c) is the removal of salt from sea water
(d) is the removal of seaweeds from sea water
Answer:
(c) is the removal of salt from sea water
Question 3.
The gradient of slope of continental slope region can be ………………….
(a) around 2° to 5°
(b) between 12° to 15°
(c) around 2° to 4°
(d) between 2° to 5°
Answer:
(d) between 2° to 5°
Question 4.
The oceanic trenches generally occur along plate boundaries and are associated with …………………
(a) active volcanoes and strong earthquakes
(b) folds and fault
(c) sedimentation
(d) deep sea movements
Answer:
(a) active volcanoes and strong earthquakes
Question 5.
Limestones are formed extensively in the tropical oceans of the world as a result of ………………….
(a) volcanic heat
(b) precipitate material by corals and plants
(c) sediments brought by the rivers
(d) evaporation of sea water
Answer:
(b) precipitate material by corals and plants
Question 6.
On tropical coasts, ………………….. vegetation is found abundantly.
(a) evergreen
(b) mangrove
(c) deciduous
(d) coniferous
Answer:
(b) mangrove
Question 7.
The ……………….. Ocean route is the most important and busiest ocean route in the world.
(a) Atlantic
(b) Pacific
(c) Indian
(d) Arctic
Answer:
(a) Atlantic
Question 8.
The deposition of sediments is limited in ………………….
(a) Continental shelf
(b) Continental slope
(c) Abyssal plains
(d) Oceanic deeps
Answer:
(b) Continental slope
Question 9.
The submerged ……………….. on the ocean floor are called oceanic ridges.
(a) mountains
(b) Islands
(c) deeps
(d) plateaus
Answer:
(a) mountains
Question 10.
The ………………… are isolated habitats that have evolved slowly over millions of years to support communities.
(a) ridges
(b) mountains
(c) plateaus
(d) seamounts
Answer:
(d) seamounts
Identify the correct correlation.
A : Assertion
R : Reasoning
Question 1.
A – The oceanic trenches are the deepest parts of the oceans.
R – These trenches can be thousands of metres deep.
(a) Only A is correct.
(b) Only R is correct.
(c) Both A and R are correct and R is the correct explanation of A.
(d) Both A and R are correct but R is not the correct explanation of A.
Answer:
(c) Both A and R are correct and R is the correct explanation of A.
Identify the incorrect factor.
Question 1.
Continental Islands in India are-
(a) Minicoy
(b) Seven Islands of Bombay
(c) Amindivi
(d) Andaman
Answer:
(d) Andaman
Question 2.
The relief of ocean floor contain-
(a) depression
(b) continental shelf
(c) abyssal plain
(d) ocean trench
Answer:
(a) depression
Question 3.
The biotic resources on ocean floor are-
(a) plankton
(b) seaweeds
(c) minerals
(d) fish
Answer:
(c) minerals
Question 4.
The abiotic resources on ocean floor are-
(a) limestone
(b) mollusc
(c) gypsum
(d) mineral oils
Answer:
(b) mollusc
Question 5.
The biotic resources on ocean floor are-
(a) whale
(b) corals
(c) sodium chloride
(d) seahorse
Answer:
(c) sodium chloride
Question 6.
Abiotic resources on ocean floor are-
(a) shrimp
(b) potassium
(c) sodium chloride
(d) natural gas
Answer:
(a) shrimp
Question 7.
Marine pollution occurs due to-
(a) industrial effluents
(b) disposal of solid waste
(c) leakage of oil from oil exporting ships
(d) burning of waste
Answer:
(d) burning of waste
Question 8.
The richest Ashing grounds in the world are-
(a) Dogger bank
(b) Konkan coast
(c) Grand bank
(d) Georges bank
Answer:
(b) Konkan coast
Give geographical reasons.
Question 1.
The very existence of marine life is threatened.
Answer:
The very existence of marine life is threatened because-
- Due to human activities, the ocean is polluted on a large scale.
- The leakages of oil from oil transporting ships, oil extraction from coastal areas, disposal of solid waste containing radioactive matter, atomic tests etc., are causing large scale pollution of oceanic waters.
- The effluents brought by river discharges, the disposal of waste from coastal cities, the waste from industries and many other similar factors are polluting the oceanic waters.
Question 2.
The seas and oceans are the most convenient natural medium of transport.
Answer:
The seas and oceans are the most convenient natural media of transport because-
- Sea or ocean transport is used for both passengers and goods transport.
- The most important aspect of sea and ocean transport is that it is the cheapest mode of transport than any other modes of transport.
- The heavy goods, machinery, vehicles etc., can be carried by ocean transport conveniently and at cheaper rate.
- The transport of goods and passengers between the countries is not possible by rail and road transport, air transport has limitations; therefore, sea or ocean transport is useful and convenient for international trade.
- For example, Suez Canal connects the Mediterranean Sea to the Indian Ocean via. the Red Sea, making it the shortest maritime route to Asia from Europe.
Question 3.
Ocean tourism is becoming popular.
Answer:
Ocean tourism is becoming popular because-
- Ocean tourism is developed along the coastal areas of seas and oceans.
- Generally, water sports activities such as scuba diving, surfing, water skiing, etc., are developed along the coastline. For example, sport activities along the coast of Goa.
- There is a beautiful scenery along the coastline due to greenery of trees.
- Along the coast we find huge water bodies of seas and oceans, clean air and coolness due to nearness to water. Therefore, many resorts, hotels, marina, etc., are developed and coastal areas have become popular for tourism.
- The cruise tourism is also increasing.
Differentiate between.
Question 1.
Continental Shelf and Continental Slope.
Answer:
| Continental Shelf | Continental Slope |
| (i) The portion of the continents that is submerged under water and borders the coastal areas is known as a continental shelf. | (i) After the extent of continental shelf is over, there is a sharp drop in the ocean floor. This is called continental slope. |
| (ii) They are broad, shallow and gently-sloping plains covered by water. | (ii) The slope is steep and stretches over limited area. |
| (iii) The depth of the continental shelf from the sea level is about 180 to 200 m. | (iii) The depth of the continental slope is from 200 m to 4000 m from the sea level. |
| (iv) Sunlight reaches up to the bottom of the continental shelf and hence fishing is done on a large scale in this region. | (iv) Sunlight does not reach the bottom of the continental slope and moreover due to the steep slope fishing cannot be done in this region. |
| (v) The continental shelves contain the world’s largest reservoirs of natural oil and gas. Besides oil and gas, minerals are also found here. Diamonds, chromite, ilmenite, magnetite, platinum, gold and phosphorite deposits are also found here. Sand, gravel aggregates and industrial silica sand are the most important of hard minerals now extracted in the near offshore zone. | (v) Methane hydrate, a compound of water and methane, is present on the continental slopes. On the slope, we find many traces of submarine landslide activity, ocean canyons and huge avalanche fans. |
Question 2.
Oceanic Deeps and Oceanic Trenches.
Answer:
| Oceanic Deeps | Oceanic Trenches |
| (i) At places, deep, narrow and steeply sloping depressions are found on the ocean floor. The shallow depressions are called deeps. | (i) At places, deep, narrow and steeply sloping depressions are found on the ocean floor. The deeper depressions are called ocean trenches. |
| (ii) Active volcanoes and earthquakes are not seen in oceanic deeps. | (ii) Trenches are formed at convergent plate boundaries. Active volcanoes and earthquakes generally occur along the plate boundaries of oceanic trenches. |
| (iii) The Romanche Trench in the Atlantic Ocean close to the equator. | (iii) The Mariana Trench in the Pacific Ocean is 11 kms deep. |
Answer the following question by using the given map.
Question 1.
In which ocean are the Madagascar islands located?
Answer:
Madagascar islands are located in the Indian Ocean.
Question 2.
Mention the location of Georges Bank.
Answer:
Georges Bank is located along the north eastern coastline of U.S.A.
Question 3.
Where is the Congo Canyon located?
Answer:
The Congo Canyon is located along the western coastline of South Africa.
Question 4.
Name the group of islands located in the Pacific Ocean.
Answer:
The Hawaiian Islands are located in the Pacific Ocean.
Question 5.
Name the deepest trench in the Indian ocean.
Answer:
The deepest trench in the Indian Ocean is the Java Trench.
Write short notes on.
Question 1.
Causes of climate change
Answer:
The portion of the continents that are submerged under water and borders the coastal areas is known as a continental shelf.
They are broad, shallow and gently-sloping plains covered by water.
The continental shelf does not extend into the ocean uniformly. Near some coasts, it is narrow while in some parts it may extend for hundreds of kilometres. For example, they are almost absent or very narrow along the coasts of Chile, Sumatra etc., while the Siberian coast near the Arctic Ocean is around 1500 km in width.
Generally, its depth from the sea level is about 180 m to 200 m.
As the sunlight reaches this part of the ocean bed, it is rich in plankton. These millions of microscopic organisms found in sea water are an important food for fish. Millions of fishes thrive here. The shelf has some of the richest fishing grounds in the world, such as the Grand Banks and Georges Bank in North America.
The continental shelves contain the world’s largest reservoirs of natural oil and gas. For example, the Mumbai High in Arabian sea. Besides oil and gas, minerals are also found here.
Diamonds, chromite, ilmenite, magnetite, platinum, gold and phosphorite deposits are common. Sand, gravel aggregates and industrial silica sand are the most important of hard minerals now extracted in the near offshore zone.
Question 2.
Desalination
Answer:
- Sea water contains lot of salt, so it is not useful for drinking or irrigation purpose. Therefore, it is necessary to convert the sea water into fresh water.
- Desalination is the process of removal of salt from sea water and converting sea water into fresh water.
- Desalination is done by heating water or freezing water or by electrical processes.
- The desalination process is very expensive, therefore it is used where there is acute shortage of water.
- The Minjur Desalination Plant is the largest in India, located at Kattupalli village, a northern suburb of Chennai on the coast of the Bay of Bengal that supplies water to the city of Chennai.
- These desalination plants are more used in developing countries since the cost for processing is high. Desalination plants are located in Saudi Arabia, Oman, Cyprus, Algeria, Spain and UAE.
- Desalination plants have adverse effect on the coastal environment. Small sea organisms like plankton and baby fish may be killed. Their food chain is disturbed.
- It is still used in some countries to get fresh water.
Draw a neat and labelled diagram of the ocean floor.
Answer:
Answer in detail.
Question 1.
Explain uses of the oceans for other purposes.
Answer:
Following are the other uses of oceans:
For energy:
- Tidal Energy : The phenomenon of tides releases large amounts of energy. Thus, tidal energy can be used to generate electricity.
- Thermal energy : The temperature differences of sea water help in generating the energy. The surface water of the tropical region may have 25°C to 30°C of temperature while the deep-sea water may have less than 5°C. This gradient of temperature is used to run a generator to produce electricity.
For drinking water : Due to high salt content in sea water, it is not suitable for drinking or for irrigation directly. But sea water can be converted into fresh water.
Trade and transport : Maritime transport is the transport of people or cargo by water. Transportation by water is cheaper than any other modes of transport. The seas and oceans are the most convenient natural medium for transport. For example, Suez Canal connects the Mediterranean Sea to the Indian Ocean via. the Red Sea, making it the shortest maritime route to Asia from Europe.
Tourism : Ocean tourism comes in many forms like cruises, scuba-diving, fishing, beach tourism, etc. Such activities are increasingly becoming popular. In many areas, massive new tourist developments have been built which include resorts and marinas. These activities, in turn, affect the ocean habitats and environment.
Question 2.
Explain the biotic resources on the ocean floor.
Answer:
- The biotic resources on the ocean floor bottom include plants and animals.
- The oceans provide habitat to thousands of species of marine plants and animals which are food for many organisms.
- There are many marine animals like fish, crabs, mollusks tortoises, prawns, etc.
- There are many plant varieties such as seaweeds, mangroves, medicinal plants, and many more marine plants.
- Many sea animals provide oil, leather, cattle feed, glue, and some other products. Seaweeds are also used as food. Seaweeds added in fertilizers and skincare ointments, etc.
- Mangrove forests provide wood for fuel, furniture, and various products useful for man. Mangroves provide food and shelter to marine life.
- There are also micro-organisms that produce organic material, they are called plankton. Plankton is one of the favourite fish foods. Marine life depends upon plankton.
- Coral reefs are a major part of the ocean ecosystem. Tourism develops in the areas where corals are found. For example, the Great Barrier Reef in Australia attracts tourists from all around the world.
Thus, biotic resources on the ocean floor are valuable.
Question 3.
Explain the importance of abiotic resources on the ocean floor.
Answer:
- There are many abiotic resources on the ocean floor and most of them are not exploited yet.
- The most common resources are sodium chloride, gypsum, limestone, etc. Sodium chloride is a common salt.
- Gypsum deposits are collected from the ocean floor. Gypsum is used in making Plaster of Paris.
- The material which precipitates from the body of corals results in the formation of limestone. The metamorphic form of limestone is a marble.
- A large number of metallic and non-metallic minerals are found on the ocean floor. These are rich deposits of copper, manganese, zinc, cobalt, platinum, etc.
- The most important mineral related to our day-to-day life is extracted from the seafloor, that is mineral oil and natural gas. For example, Bombay High – is an oil mining area in the Arabian Sea.
- When we obtain non-biotic resources from the ocean floor, it may cause a disturbance in ecological balance. The drilling machines may disturb marine organisms. Therefore, care should be taken to maintain the ecological balance of the ocean environment.