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(ii) Sand dunes : These are the hills of sand formed by the accumulation of sand and
shaped by the movement of winds. Dunes are formed when wind deposits sand in the
form of a law hill. Dunes are generally formed in groups.
(iii) Loess : When the eroded sand gets deposited in large areas, it is called loess. They are
usually found in China.
Mushroom Rocks Sand Dunes Loess
Now I Know :
There are seven major lithospheric plates.
Movements of molten magma cause tectonic movements which cause changes on the earth’s surface.
Endogenic forces are responsible for the occurrence of earthquake, volcanoes, landslides, etc.
Features formed by rivers are V shaped valleys, waterfalls, flood plains, meanders, ox-bow lakes, levees and deltas.
Sea caves, arches and stacks are the erosional features of ocean waves.
Glaciers form U shaped valleys and moraines.
Wind action results in formation of mushroom rocks, loess and sand dunes.
(Assessment of Learning Outcome)
A. Tick () the correct option :
1. Which one of the following is not associated with the sudden forces?
(a) Earthquakes (b) Volcanoes
(c) Landslides (d) Building mountains
2. Which one of the following is used to measure the intensity of an earthquake?
(a) Wind vane (b) Richter scale (c) Mono scale (d) None of these
3. What occurs when crustal plates diverge or move apart?
(a) Earthquake (b) Volcano (c) Deposition (d) Erosion
4. The process of reduction of height of landform is called :
(a) erosion (b) degradation (c) aggradation (d) none of these
5. The removal of outer layer of rocks in the natural environment is called :
(a) erosion (b) deforestation (c) degradation (d) none of these
B. Fill in the blanks :
1. Sudden vibrations by the movements of lithospheric plates are called ________________.
Social Studies-7 33
