Answer the following questions.

(i) Why do the plates move?

(ii) What are exogenic and endogenic forces?

(iii) What is erosion?

(iv) How are flood plains formed?

(v) What are sand dunes?

(vi) How are beaches formed?

(vii) What are ox-bow lakes?

(i) The Lithospheric plates move around because of the movement of the molten magma inside the Earth.

(ii) Earth’s movements are divided on the basis of the forces which cause them. The ones that work on the Earth’s surface are called exogenic forces while the ones that work in the Earth’s interior are called endogenic forces. The erosional and depositional activities of wind and water are examples of exogenic forces. Earthquakes and volcanoes are examples of endogenic forces.

(iii) Erosion is the weathering or wearing away of the landscape by different agents like wind, water and ice.

(iv) During its course through a plain, a river sometimes overflows its banks. This leads to the flooding of the neighbouring areas. As it floods, the river water deposits layers of fine soil and sediments on its banks. This leads to the formation of a flat, fertile flood plain.

(v) In deserts, when wind blows, it lifts and transports sand from one place to another. When it stops blowing, the sand particles fall and get deposited in low hill-like structures called sand dunes.

(vi) The erosional and depositional activities of the sea waves give rise to different coastal landforms. A beach is one such coastal landform. It is formed when the sea waves deposit sediments along the sea shore.

(vii) An ox-bow lake is a crescent-shaped lake formed by a meandering river. During its journey through a plain, a river twists and turns to form meanders. Erosion and deposition occur constantly along the sides of a meander, thereby causing the ends of its loop to come closer and closer. In due course of time, the meander loop cuts off from the river and forms a cut-off, crescent-shaped ox-bow lake.