NCERT Solutions For Class 11 Geography Chapter 4 Distribution of Oceans and Continents - 2025-26

1. Multiple choice questions.

i. Who amongst the following was the first to consider the possibility of Europe, Africa and America having been located side by side.

• (a) Alfred Wegener
• (b) Antonio Pellegrini
• (c) Abraham Ortelius
• (d) Edmond Hess

Answer: (c) Abraham Ortelius

ii. Polar fleeing force relates to:

• (a) Revolution of the Earth
• (b) Gravitation
• (c) Rotation of the earth
• (d) Tides

Answer: (c) Rotation of the earth

iii. Which one of the following is not a minor plate?

• (a) Nazca
• (b) Arabia
• (c) Philippines
• (d) Antarctica

Answer: (d) Antarctica

iv. Which one of the following facts was not considered by those while discussing the concept of sea floor spreading?

• (a) Volcanic activity along the mid-oceanic ridges.
• (b) Stripes of normal and reverse magnetic field observed in rocks of ocean floor.
• (c) Distribution of fossils in different continents.
• (d) Age of rocks from the ocean floor.

Answer: (c) Distribution of fossils in different continents.

v. Which one of the following is the type of plate boundary of the Indian plate along the Himalayan mountains?

• (a) Ocean-continent convergence
• (b) Divergent boundary
• (c) Transform boundary
• (d) Continent-continent convergence

Answer: (d) Continent-continent convergence

2. Answer the following questions in about 30 words.

i. What were the forces suggested by Wegener for the movement of the continents?

Answer: Wegener suggested two forces for the movement of the continents: the pole-fleeing force (due to Earth’s rotation, causing a bulge at the equator) and the tidal force (created by the gravitational attraction of the Moon and the Sun).

ii. How are the convectional currents in the mantle initiated and maintained?

Answer: Convectional currents in the mantle are initiated and maintained by the thermal differences due to radioactive elements. The heated mantle material rises, spreads, cools, and sinks back, forming continuous convection currents.

iii. What is the major difference between the transform boundary and the convergent or divergent boundaries of plates?

Answer: At transform boundaries, plates slide horizontally past each other, neither creating nor destroying crust. At convergent and divergent boundaries, crust is either destroyed (subducted) or created (spread), respectively.

iv. What was the location of the Indian landmass during the formation of the Deccan Traps?

Answer: During the formation of the Deccan Traps (around 60 million years ago), the Indian landmass was situated close to the equator and was still moving northward towards the Eurasian Plate.

3. Answer the following questions in about 150 words.

i. What are the evidences in support of the continental drift theory?

Answer: The continental drift theory is supported by several evidences:

• Jig-saw fit: The coastlines of Africa and South America match remarkably.
• Rocks of same age: Ancient rock belts found across different continents match in age and type (Brazil and Western Africa).
• Tillite deposits: Glacial tillites found in India, Africa, Falkland Island, Madagascar, Antarctica, and Australia suggest prolonged glaciation in southern continents.
• Placer deposits: Gold deposits in Ghana match source rocks found in Brazil, implying the continents were once connected.
• Distribution of fossils: Identical fossils, such as Mesosaurus, found in distant continents demonstrate their former connection.

These evidences collectively support the idea that continents were once joined together and have since drifted apart.

ii. Bring about the basic difference between the drift theory and Plate tectonics.

Answer: The drift theory, proposed by Wegener, suggested that continents alone moved over Earth's surface, initially as a single supercontinent (Pangaea), which then split apart. However, it could not explain the force behind the drift convincingly.

Plate tectonics, a modern theory, states that the Earth's lithosphere is divided into several major and minor plates made of both continental and oceanic crust. These plates move as rigid units over the semi-fluid asthenosphere due to convection currents in the mantle.

Unlike the drift theory, plate tectonics explains the movement of both continents and oceans as parts of these large plates and provides a mechanism for their movement, such as sea floor spreading, subduction, and transform faulting.

iii. What were the major post-drift discoveries that rejuvenated the interest of scientists in the study of distribution of oceans and continents?

Answer: Several post-drift discoveries revived interest in oceanic and continental distribution:

• Ocean floor mapping revealed submerged mountain ranges (mid-oceanic ridges) and deep-sea trenches.
• Rocks from oceanic crust were found to be much younger than continental rocks.
• Palaeomagnetic studies identified symmetric strips of normal and reversed magnetic polarity on the ocean floor.
• Age patterns showed rocks are youngest near mid-oceanic ridges and oldest away from them.
• Thin sediment layers on the ocean floor indicated recent formation.

These findings led to the concepts of sea floor spreading and plate tectonics, offering a scientific explanation for continental movement.

Importance of Plate Tectonics and Continental Drift in Geography

Understanding Distribution of Oceans and Continents helps students master key topics like continental drift and plate tectonics. Clear concepts will not only boost your Geography score but also make Earth science fascinating and relevant for higher studies.

Reviewing NCERT Solutions for Distribution of Oceans and Continents (2025-26) ensures thorough coverage of all questions. Regular revision of exercise-based topics helps reinforce essential ideas and strengthens your memory for quick recall in exams.

For exam success, focus on diagrams, definitions, and key differences between theories. Practicing with the latest NCERT Geography solutions will increase your confidence, helping you score higher in both objective and descriptive exam formats.

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