Consider the following statements regarding the interior of the Earth: 1. The crust is the thickest layer of the Earth. 2. The oceanic crust is thinner than the continental crust. 3. The mantle extends up to a depth of only 100 km. Which of the statements given above is/are correct?

The correct option is (b). Explanation The interior of the Earth is divided into three main concentric layers based on chemical composition and physical properties: the Crust, the Mantle, and the Core. These layers vary significantly in thickness, density, and composition. Statement-wise Analysis: - Statement 1 is Incorrect. The crust is the thinnest layer of the Earth, constituting less than 1% of the Earth's volume. Its thickness ranges from roughly 5 km to 70 km. In contrast, the mantle is the thickest layer by volume (approximately 84%) and mass (approximately 67%), extending to a depth of 2,900 km. - Statement 2 is Correct. The oceanic crust is significantly thinner than the continental crust. The mean thickness of the oceanic crust is approximately 5 km, whereas the continental crust has a mean thickness of around 30 km, reaching up to 70 km in major mountain systems like the Himalayas. - Statement 3 is Incorrect. The mantle extends from the Mohorovicic discontinuity (the base of the crust) to a depth of 2,900 km (the Gutenberg discontinuity). The depth of 100 km generally corresponds to the approximate thickness of the Lithosphere (which includes the crust and the uppermost solid mantle), not the full extent of the mantle. Key Takeaway: The Crust is the outermost and thinnest layer (5–70 km), with oceanic crust being thinner and denser than continental crust. The Mantle is the most voluminous layer, extending from the base of the crust down to the Core-Mantle boundary at 2,900 km.

NCERT Class 7 Geography — Chapter 1: Inside Our Earth

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Consider the following statements regarding the interior of the Earth:

The crust is the thickest layer of the Earth.
The oceanic crust is thinner than the continental crust.
The mantle extends up to a depth of only 100 km.

Which of the statements given above is/are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A1 only
B2 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (b).

Explanation

The interior of the Earth is divided into three main concentric layers based on chemical composition and physical properties: the Crust, the Mantle, and the Core. These layers vary significantly in thickness, density, and composition.

Statement-wise Analysis:

Statement 1 is Incorrect.
The crust is the thinnest layer of the Earth, constituting less than 1% of the Earth's volume. Its thickness ranges from roughly 5 km to 70 km. In contrast, the mantle is the thickest layer by volume (approximately 84%) and mass (approximately 67%), extending to a depth of 2,900 km.
Statement 2 is Correct.
The oceanic crust is significantly thinner than the continental crust. The mean thickness of the oceanic crust is approximately 5 km, whereas the continental crust has a mean thickness of around 30 km, reaching up to 70 km in major mountain systems like the Himalayas.
Statement 3 is Incorrect.
The mantle extends from the Mohorovicic discontinuity (the base of the crust) to a depth of 2,900 km (the Gutenberg discontinuity). The depth of 100 km generally corresponds to the approximate thickness of the Lithosphere (which includes the crust and the uppermost solid mantle), not the full extent of the mantle.

Key Takeaway:
The Crust is the outermost and thinnest layer (5–70 km), with oceanic crust being thinner and denser than continental crust. The Mantle is the most voluminous layer, extending from the base of the crust down to the Core-Mantle boundary at 2,900 km.

Your note

More from Chapter 1: Inside Our Earth

With reference to the composition of the Earth’s crust, the term ‘Sial’ refers to which of the following combinations?

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Consider the following statements regarding the Earth's core: 1. It is the innermost layer with a radius of about 3500 km. 2. It is mainly composed of silica and magnesium. 3. It has very high temperature and pressure. Which of the statements given above is/are correct?

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Which of the following correctly represents the volume composition of the Earth’s layers?

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The oceanic crust mainly consists of which of the following mineral constituents?

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Consider the following pairs regarding rock types and their word origins: 1. Igneous : Latin word meaning 'fire' 2. Sedimentary : Latin word meaning 'settle down' 3. Metamorphic : Greek word meaning 'change of form' 4. Fossils : Latin word meaning 'hard rock' How many of the above pairs are correctly matched?

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The correct option is (b).

Explanation

Statement-wise Analysis:

Statement 1 is Incorrect.
The crust is the thinnest layer of the Earth, constituting less than 1% of the Earth's volume. Its thickness ranges from roughly 5 km to 70 km. In contrast, the mantle is the thickest layer by volume (approximately 84%) and mass (approximately 67%), extending to a depth of 2,900 km.
Statement 2 is Correct.
The oceanic crust is significantly thinner than the continental crust. The mean thickness of the oceanic crust is approximately 5 km, whereas the continental crust has a mean thickness of around 30 km, reaching up to 70 km in major mountain systems like the Himalayas.
Statement 3 is Incorrect.
The mantle extends from the Mohorovicic discontinuity (the base of the crust) to a depth of 2,900 km (the Gutenberg discontinuity). The depth of 100 km generally corresponds to the approximate thickness of the Lithosphere (which includes the crust and the uppermost solid mantle), not the full extent of the mantle.