• Water and wind are the main agents of erosion and transportation which erode and carry the loosened material from one place to another
• Eg water - through streams and rivers
• Eg Wind - through dust storms.

Mass wasting, which is sometimes called mass movement or slope movement, is defined as the large movement of rock, soil and debris downward due to the force of gravity. In other words, the earth's outer crust is being 'wasted' away on a 'massive' scale and falling to lower elevations.

The decade between 1930 and 1940, saw long periods of severe droughts accompanied by extreme dust storms in North America 

Winds may erode, transport, and deposit materials and are effective agents in regions with sparse vegetation.

• Deposition of materials in lowlands which causes the filling up of the land and its upliftment is called Aggradation. Hence option A is correct.
• Degradation is the lowering of the land.
• Wethering is the breakdown and wearing away of rocks.
• Gradation is the levelling of the land.

Denudation is the process of lowering and leveling of the earth surface by gradual breaking and wearing away of such earth’s features. The agents which promote these breaking and lowering of the earth’s surface are called the agents of denudation.  Examples of agents of denudation are wind, running water, ice and waves.

Runoff, streams, and rivers carry sediment to the oceans. The sediment in ocean water acts like sandpaper. Over time, they erode the shore. The bigger the waves are and the more sediment they carry the more erosion they cause and form from wave erosion.

Ox bow lake are formed by the erosional work of river.

When weathered particles move down due to gravity alone, the process is called mass movement. Mass movement occur in two ways; it is rapid on sleeper slopes while it is slower on gentle slopes.

Like weathering and mass movements, erosion is also an external process. Erosion occurs through various agents. Wind, running water, glaciers, sea water and groundwater.

When weathered materials move very rapidly and come down the slope it is called rapid mass movement. The main reason of rapid mass movement are:-

• Rockfalls
• Landslides
• Land subsidence

When weathered particles move down due to gravity alone, the process is called mass movement. Mass movement occur in two ways; it is rapid on sleeper slopes while it is slower on gentle slopes.

When the weathered materials do not move downward but sink "in situ", this is called slumping. Such rapid mass movements may also occur beccause of earthquakes.

In periglacial regions along the slopes, small layers of soil accumulate because of the movement of soil. This is called solifluction.

When weathered particles move down due to gravity alone, the process is called mass movement. Mass movement occur in two ways; it is rapid on sleeper slopes while it is slower on gentle slopes.

Slumping in simple terms is recurring downward movements of rock debris. Slump is slipping of one or several units of debris with a backward rotation with respect to the slope over which the movement takes place. Thus, it is the process by which the weathered materials do not move downward but sink in situ.

The factors that determine the deposition of sediments are the length of the rivers, volume of water, amount of sediments, and the slope of the river and the earth's surface.

When gravity alone causes rock or sediment to move down a slope, the erosion is called mass movement. This process is also known as mass wasting. It is a process where a mass of rock debris down the slope under the direct influence of gravity. Weathering is not essential for mass movement, though it helps mass movement. Mass movement has two major classes namely:

Solifluction is a process covered under the slow mass movements. It is a process that involves slow downslope flowing of soil mass or fine-grained rock debris saturated or lubricated with water. It is because permafrost (ground that remains completely frozen) is impermeable to water, soil overlying may become oversaturated and slide downslope under the pull of gravity. Thus, in periglacial regions along the slopes, some small layers of soil accumulated because of the movement of the soil are known as solifluction. 

Sea cliffs are usually formed by the process of weathering and erosion. In coastal areas the sea waves erode away the base of the headland. The part of rock that remains form a sea cliff.

A headland is an area of land that extends into a large body of water. It is often a cliff or other elevated landform overlooking a sea or ocean. It is formed when a softer rock in pushed or eroded inwards, the hard rocks sticks out in the sea. 

Landforms like flood levees, flood plains and deltas are formed because of the depositional works of the river.

Sea forms create erosional and depositional landforms. Steep rocky coast rising almost vertically above sea water is called sea cliff which is very precipitous with overhanging crest. Sea canes are formed by the mechanical erosion of rocks by the action of sea. A lagoon is a shallow body of water separated from a larger body of water by barrier islands or reefs. They form in areas with small tidal range.

Extensive loess deposits are found in northern China, the Great Plains of North America, central Europe, and parts of Russia and Kazakhstan. The thickest loess deposits are near the Missouri River in the U.S. state of Iowa and along the Yellow River in China.