Which one of the following describes the Lithosphere?

The lithosphere is defined as the rigid, outermost shell of the Earth. It is mechanically distinct from the underlying layers due to its brittle nature and strength [3]. Structurally, the lithosphere comprises the entire crust (both continental and oceanic) and the uppermost portion of the mantle [7]. This layer typically varies in thickness from approximately 10 km in oceanic regions to about 200 km beneath continental areas [5]. It sits atop the asthenosphere, which is a more ductile, semi-solid part of the upper mantle that allows the lithospheric plates to move [6]. While the Earth is chemically divided into the crust, mantle, and core, the mechanical classification groups the crust and the rigid top part of the mantle together as the lithosphere [2]. Therefore, the lithosphere is correctly described as the combination of the crust and upper mantle.

Sources

1. [3] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Lithosphere > p. 10
2. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 4: Earths Interior > Lithosphere > p. 54
3. [4] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Interior of the Earth > The Mantle > p. 23
4. [7] https://education.nationalgeographic.org/resource/lithosphere/
5. [5] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 7: Tectonics > 7.4. Plate Tectonics > p. 101
6. [6] https://www.noaa.gov/jetstream/tsunamis/tsunami-generation-earthquakes/jetstream-max-plate-tectonics-and-earthquakes
7. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 4: Earths Interior > 4.1. The Internal Structure of The Earth > p. 52