Endogenic and exogenic forces

Endogenic forces are driven by energy generated inside the Earth. For exams remember endogenic means internal origin.

Folding occurs due to internal pressure in the Earth's crust. In exams treat mountain building as an endogenic process.

Endogenic forces create relief such as mountains and plateaus. For exams remember them as constructive forces.

Exogenic forces erode high areas and deposit material in low areas. In exams connect them with leveling.

An earthquake occurs due to sudden release of energy inside the Earth. In exams consider it a sudden endogenic event.

Volcanic activity has its source in the Earth's interior. In exams link magma with an internal source.

In mass movement material moves downslope under gravity. For exams connect it directly with gravity.

Weathering breaks material and erosion removes it. For exams remember the difference between breakdown and transport.

Endogenic processes use internal energy and exogenic processes mostly use solar energy. In exams classify them by energy source.

Direct answer: Option A, bending of the crust due to compression. Fold mountains form when rock layers are squeezed by converging plates. Instead of breaking immediately, some layered rocks bend into arches and troughs; uplift then produces mountain ranges. The Himalaya are a major example of mountains associated with plate convergence and folding, although thrusting also occurs. Option A is correct because it states the essential force and response: compression causes bending. Option B is wrong because sand deposition can build dunes or sedimentary layers but does not create tectonic fold mountains. Option C is wrong because chemical weathering breaks down minerals at the surface and generally lowers or weakens relief rather than producing the original folds. Option D is wrong because wave erosion cuts coasts and removes material; it does not compress deep crust into folds. Memory cue: compression makes layers bend; bending makes fold mountains.

In faulting crustal rocks break and are displaced. In exams remember both breaking and slipping.

Exogenic processes cut down high areas and move land toward leveling. In exams treat them as lowering processes.

A river cuts rocks on the surface to form valleys. In exams consider river action an exogenic process.

Crustal uplift can occur slowly due to internal forces. For exams treat slow crustal movements as endogenic.

When the carrying capacity of river wind or glacier decreases material is deposited. For exams connect deposition with reduced energy.

Solar energy affects temperature rainfall and the water cycle. In exams consider the Sun a major energy source for exogenic processes.

Endogenic forces can form mountains plateaus and volcanic features. In exams understand them as landform builders.

Exogenic forces cut high areas and remove material. For exams remember erosion and leveling together.

Alluvium is deposited by surface action of rivers. For exams connect alluvial plains with river deposition.

Endogenic forces build relief and exogenic forces modify it. In exams view landscape as a dynamic system.

Plateau uplift may be linked with internal crustal movements. For exams treat uplift as an endogenic process.

Diastrophism is related to slow internal movements of the crust. For exams connect it with folding and faulting.

Earthquakes and volcanoes show sudden effects of internal energy. In exams treat them as sudden endogenic events.

Slow endogenic processes cause uplift subsidence and deformation over long periods. In exams identify the time scale.

Weathering loosens material and erosion removes it. For exams understand the sequence of these processes.