Chapter 9 Topic A General Introduction And Physical Environment Of North America Short Analytical Type Questions
Question 1. Write a note on the boundaries of North America.
Answer:
Boundaries Of North America:-
The boundaries of North America can be described in the following ways-
Coordinates:
North America extends from 7° North latitude (the southernmost tip of Panama) 84°North latitude (northern tip of Greenland) and 20° West longitude to 173° West longitude.
Geographical boundaries:
The continent of North America is shaped somewhat like an inverted triangle. To the east of the continent lies the Atlantic Ocean, to the west lies the Pacific Ocean, to the north is the Arctic Ocean while to the south is the Pacific Ocean, the Gulf of Mexico, and the Panama Canal.
The Bering Strait, which lies to the northwest, separates North America from Asia. The Panama Canal, which lies to the south, separates it from South America.
The seas around North America are dotted with a number of islands which are also part of this continent such as Greenland in the north (the world’s Newfoundland in the east, Cuba and Jamaica in the largest island), the south, and the Queen Charlotte Islands to the west.
WBBSE Class 8 North America Short Answer Questions
Question 2. What is the Western Cordilleras?
Answer:
Western Cordilleras:-
A long, expansive stretch of mountainous land that stretches from Alaska in the north to the Isthmus of Panama in the south along the western part of North America is known as the Western Cordilleras.
This is made up of three almost parallel mountain ranges- the Rockies, the Alaska and the Coast Range, and the plateau areas in between. The word cordillera means chain or rope. This region is named so because of the chain of three continuous ranges.
Question 3. Describe the coastal plains of North America.
Answer:
Coastal Plains Of North America:-
The entire coastline of North America falls under the physical classification of plains. Apart from the coast of the Gulf of Mexico and that of the Atlantic in the south and southwest, the remaining areas are quite narrow.
The coast of the Northern (Arctic) Ocean in the north of the continent is quite wide while that in the west is narrow because the Western Cordilleras rise almost from the shoreline of the Pacific Ocean.
The coastal plains of the Gulf of Mexico are quite wide as well. There are several saline water bodies, lagoons, and deltas along the Coastal Plains. The highest part of this area is less than 200m in altitude.
Short Answer Questions on Physical Environment of North America
Question 4. Write a short note on the Colorado River.
Answer:
Colorado River:-
The Colorado River is the main river flowing through the western part of North America.
1. Length:
The Colorado River is about 2300km in length.
2. Source and mouth:
This river rises in the Rocky Mountains and then flows into Lake Mead before moving towards Death Valley and then the Mojave desert before finally discharging into the Gulf of California through Mexico.
This river has carved the world’s largest and deepest canyon, the Grand Canyon, in the state of Arizona in the USA. The rivers Gila, Virgin, Fraser, and Yukon Columbia are a few of the tributaries of the Colorado River.
3. Significance:
The main significance of the Colorado River is that it has enabled an arid, near-desert region to become an agriculturally dominant region.
Several dams and reservoirs have been constructed on this river to facilitate municipal water supply to a large population and also for irrigation and hydroelectric power. Among these, the Hoover Dam is notable.
WBBSE Class 8 Geography North America Answers
Question 5. Write a brief note on Mississippi- Missouri.
Answer:
Mississippi- Missouri:-
Mississippi, the main river flowing through North America, has Missouri as its main tributary and they form a vast river system.
1. Source and mouth:
The Mississippi originates from Lake Itasca in the Shield area adjacent to Lake Superior and it empties into the Gulf of Mexico.
2. Length:
The Mississippi-Missouri flows over a distance of 6270 km. This means that if both rivers are considered, the Mississippi-Missouri is the fourth longest river in the world.
3. Tributaries:
The main tributary of the Mississippi is the Missouri which rises in the Rocky Mountains and joins the Mississippi near St. Louis port.
Two of the Mississippi’s right-bank tributaries are the Red and Arkansas and two left-bank tributaries are Ohio and Tennessee.
4. Significance:
This river is navigable. St. Louis, St. Paul, Minneapolis, Kansas City, etc., are important port cities that have developed along its course. The culturally rich city of New Orleans has developed at the estuary of the river.
Question 6. Briefly write about McKenzie River.
Answer:
McKenzie River:-
Canada’s longest and the second longest river in North America is McKenzie.
1. Length:
The river flows for 4200km before emptying into the sea.
2. Source and mouth:
The Peace river, the headstream of the McKenzie, originates in the Rockies and then flows northwards where it meets the Athabasca River to form the Slave river which rises from a delta in Alberta.
These two rivers then together flow into the Great Slave Lake from which they rise as one river, the McKenzie. The river then divides into various separate distributaries and discharges into the North Sea after creating the vast McKenzie Delta.
This river is navigable in summer but freezes in winter.
Understanding North America’s Physical Environment for Class 8
Question 7. Write briefly about the St. Lawrence River.
Answer:
St. Lawrence River:-
St. Lawrence is the primary driver of the Great Lakes region as it connects five lakes.
1. Source: Lake Ontario
2. Length: The river flows for about 1120 km.
3. Mouth: After flowing through the lakes Superior, Michigan, Huron, Erie, and Ontario, this river empties itself in the Atlantic Ocean. It is known by different names at different parts of its course
- Between lakes superior and Huron, it is known as the St. Mary river,
- Between lakes Huron and Erie, it is known as the St. Clare river,
- Between Erie and Ontario, it is known as the Niagara river.
4. Importance:
The importance of the St. Lawrence Waterway is unparalleled. Seafaring vessels can reach up to 1600km into the interior of the continent through this waterway.
In its non-navigable course (for instance, Niagara Falls), canals such as the Welland Canal have been dug and lock gates have been constructed to facilitate ship transport.
Question 8. Describe the lakes of North America.
Answer:
Lakes Of North America:-
On the basis of their location, the lakes of North America are divided into two categories-
1. The lakes of the plains:
In the northern part of Central Lowland, is a chain of five famous freshwater lakes-Superior, Michigan, Huron, Erie, and Ontario. All of these are among the 14 largest freshwater lakes in the world.
Lake Superior is the largest lake (82103 sq. km) in North America and the largest freshwater lake in the world. These five lakes are collectively known as the Great Lakes. These five largest lakes originated due to glacial erosion.
These are interconnected by the St. Lawrence River. Except for Lake Michigan, the Great Lakes mark the natural boundary between Canada and the USA. Winnipeg, Great Bear, Athabasca, Great Slave, etc., are some other important lakes that have formed by the denudation of the peneplain region of the central lowland.
Class 8 Geography North America Topic A Solutions
2. Lakes of the mountain regions:
Two notable lakes in this region are the Great Salt Lake and Lake Nicaragua.
Question 9. Why do ocean currents become warm in some places and cold in others?
Answer:
Ocean Currents Become Warm In Some Places And Cold In Others:-
Based on temperature, ocean currents are of two types-warm ocean currents and cold ocean currents. Due to the earth’s spheroidal shape and the difference of the angle of incidence of sun rays, the temperature between landmass and water bodies also differ.
As the Torrid Zone (232°N to 232°S) receives direct sun rays, ocean currents are warm here. In the Temperate Zone (232°-662° latitude in both the hemispheres) the ocean water has moderate temperature, as this zone receives slanting sun rays.
On the other hand, the region belonging to the Frigid Zone (662°-90° latitude in both the hemispheres) have cold ocean currents as the water remains frozen throughout the year and the landmass remains mostly snow-covered.
Thus, the differences in temperature give rise to warm ocean currents in the Equatorial region like warm North Equatorial Currents.
On the other hand, in the polar regions, the snow-melted water gives rise to cold ocean currents like cold Bering Current, cold Labrador Current, etc.
Question 10. Why dry weather occurs in the beginning of spring on the eastern slope of the Rocky Mountain?
Answer:
Dry Weather Occurs In The Beginning Of Spring On The Eastern Slope Of The Rocky Mountain:-
A local wind named ‘Chinook’ blows along the eastern slope of the Rocky Mountains which is mainly situated in the Western Cordilleras that lie to the western part of North America. This wind is mainly warm and dry in nature.
As the water vapor holding capacity of this air becomes higher, rainfall does not occur in this region. For this reason, the Prairies lying in the eastern slope of Rocky Mountain, the areas near the north and south Dakota region, experience dry weather in the beginning of spring.
WBBSE Class 8 Geography Exercise on North America
Question 11. Describe North America’s rainfall pattern.
Answer:
North America’s Rainfall Pattern:-
The south-eastern, central (Florida peninsula and northern Mexico), and north-western coast of North America receive the highest rainfall-an annual average of 100 cm-200 cm or more.
The southern part of the western coast (California) and the Eastern Highlands receive a moderate rainfall-annual average of 50cm-100 cm. The Central Lowlands are at a great distance from the sea and receive less rainfall-annual average of 25 cm-50cm.
The plateau regions bounded by mountains in the southwestern part of the continent receive scanty rainfall. Both the desert region and the rainshadow region on the eastern slope of the Rockies receive an annual average of less than 25 cm.
As a result, deserts like the Sonoran and the Mojave have formed here.
Question 12. Describe the location of the Prairies of North America.
Answer:
Location Of The Prairies Of North America:-
The extensive temperate grassland that stretches over a large part of North America is known as the Prairie.
To the west of the Prairies is the Rockies, to the east is the Great Lakes region, to the north is Canada’s northwest territories and to the south is the border between the USA and Mexico.
The natural vegetation of the Prairies consists of different varieties of grasses like hay, clover, and alfalfa.
Physical Environment of North America Short Answer Guide
Question 13. Why is the dairy industry so well-developed in the Prairie region?
Answer:
Dairy Industry So Well-Developed In The Prairie Region:-
Several factors that led to the well-developed dairy industry in the Prairie region are discussed below-
1. Extensive areas for cattle grazing:
The vast stretches of grasslands and cornfields are highly suitable for cattle grazing.
2. Availability of high-grade animal fodder:
Protein-rich fodder, and grasses like hay, alfalfa, and clover are grown here. As a result, this region is highly suitable for cattle rearing.
3. Cold storage facilities:
Several technologically advanced cold storage facilities have been built for the proper preservation and storage of milk and dairy products.
4. Well-developed transport system:
This factor helps in the quick dispatch and delivery of perishable dairy products.
Question 14. Why is the Prairie region known as the ‘Bread Basket of the World’?
Answer:
Prairie Region Known As The ‘Bread Basket Of The World’:-
A special characteristic of the agricultural pattern in the Prairies is that some specific crops are grown in huge quantities in some specific parts of this region.
The northern parts are completely snow-covered in the winter. So, when the snow melts and the soil is wet in the end of winter, large quantities of wheat are grown here.
Thus this region is known as the ‘spring wheat belt’. The state of Dakota in the USA yields the highest quantity of wheat. South of the spring wheat belt, wheat is grown in the winter as the region remains snow-free.
This region is thus known as the ‘winter wheat’ belt. Throughout the year, the other part of the Prairies is under wheat cultivation. The quantities yielded are huge and so this region is also known as the ‘Bread Basket of the World’.
Chapter 9 Topic A General Introduction And Physical Environment Of North America Short Answer Type Questions
Question 1. See a map of the world and make a list of where Isthmus are seen in the world.
Answer:
The following is a list of Isthmus that can be seen on a world map-
Question 2. Why is North America known as the ‘New World’?
Answer:
North America is known as the ‘New World’ since it was discovered only 500 years ago, which is very less in a geological perspective.
Question 3. Name the volcanoes in the Western Cordillera region.
Answer:
In the southern part of the Western Cordillera, there are quite a few volcanoes in Mexico and in Central America.
Some of these are
- Popocatepetl (5426m),
- Orizaba (5636m),
- Colima (3820m).
All of these are on the Pacific Ring of Fire.
Short Answer Questions about North America’s Geography
Question 4. What is meant by ‘piedmont’?
Answer:
Piedmont:-
The word ‘piedmont’ refers to any area which lies at the foot of a mountain. This can be used to qualify a plateau, river or valley. The Cumberland Plateau is an example of a Piedmont plateau.
Question 5. The low-lying region in south-eastern California is known as the ‘Death Valley-Explain.
Answer:
The low-lying region in south-eastern California is known as the ‘Death Valley’:-
The southeastern part of California, which lies to the west of the Rocky Mountains, is about 90m deep below sea level. This is the lowest region in the western hemisphere and has a temperature of about 56°C.
This is also the hottest place in North America. The salinity of the water of this place is so high that no living creature can survive here. Thus, this valley is known as ‘Death Valley.
Question 6. Why are numerous volcanoes found along the Rockies?
Answer:
Numerous Volcanoes Found Along The Rockies:-
According to the theory of Plate Tectonics, after colliding with the North American plate, the denser and heavier Pacific Ocean plate subducted.
As a result, numerous volcanoes originated along the Rockies. Apart from this, the region is a part of the Pacific Ring of Fire and so, many volcanoes are found here.
Question 7. Why does the water of the Mississippi-Missouri turn into ice in spite of being situated in the tropical region?
Answer:
Water Of The Mississippi-Missouri Turn Into Ice In Spite Of Being Situated In The Tropical Region:-
The Appalachian Mountain runs through the eastern part of North America and on the west, the Cordilleras run from north to south. These mountain ranges act as barriers, preventing wind from the sea from entering the area in between.
Besides, cold winds from the north easily pass to the west. This cold wind is responsible for freezing the water of the Mississippi- Missouri River.
Question 8. The Newfoundland islands are always covered with dense fog-Why?
Answer:
The Newfoundland islands are always covered with dense fog:-
The warm Gulf Stream flows along the Newfoundland coast from south to north. The cool Labrador current flows from north to south.
The place where the two currents meet, the warm Gulf Stream melts the ice blocks being carried down by the Labrador Current. The water vapour caused by this comes into contact with the cool air and condenses to form fog.
So, the outer parts of Newfoundland are always shrouded in fog.
Question 9. What is meant by ‘fall line’?
Answer:
Fall Line:-
The fall line is defined as the imaginary line along which the river plunges and waterfalls occur on approximately parallel rivers.
These commonly occur on the edges of plateaus and piedmonts where streams pass from hard and resistant rocks to a plain of weak, soft rocks below. Example- the Niagara Falls.
Question 10. Why is autumn called the ‘Fall Season’ in North America?
Answer:
Autumn Called The ‘Fall Season’ In North America:-
North America is characterized by temperate forests found in the Great Lakes region and in the Eastern Highlands and coastal regions. Different types of deciduous trees such as oak, maple, elm, and ash are found here.
In autumn, the leaves of these trees turn red, yellow, or orange in color, before being shed. Thus, autumn is known as the ‘Fall Season’ in North America.
WBBSE Class 8 Geography Chapter 9 Notes
Question 11. See the map and make a list of cities of North America that experience equable and extreme climates.
Answers:
The list of few of the cities of North America which experience equable and extreme climate is given below-
Question 12. Why north the flowing rivers of North America are not suitable for navigation?
Answer:
North The Flowing Rivers Of North America Are Not Suitable For Navigation:-
The north flowing rivers of North America mainly empty into Hudson Bay, the North Sea, and the Beaufort Sea.
Hence, the mouth or the lower course of these rivers lies in the Tundra climatic region, which remains snow-covered during the entire winter season (8-9 months).
During this time, the temperature falls below the freezing point. Thus, these rivers are not suitable for navigation in winter.