Role of Rivers

Correct answer: A. Because it collects tributary water and carries it forward

The main river carries water from tributaries and surface runoff. In exams understand a river system through the main river and tributaries.

Correct answer: B. Transportation

A river carries sand silt and pebbles with its flow. In exams remember erosion transportation and deposition in order.

Correct answer: A. Decrease in slope and velocity

In the lower course river speed reduces so it deposits sediments. In exams link the lower course with deltas and flood plains.

Correct answer: B. Because the river deposits alluvial material during floods

During floods the river deposits fine silt and alluvial soil. In exams connect flood plains with agriculture.

Correct answer: A. The river has high velocity and strong vertical erosion

The steep slope in the upper course causes downward erosion. In exams link the upper course with V-shaped valleys.

Correct answer: B. Formation of oxbow lake

The direct answer is B: formation of an oxbow lake. A meander is a wide bend in a river. Water usually flows faster on the outer bank, causing erosion, and more slowly on the inner bank, causing deposition. Over time the bend becomes narrow at its neck. During a flood or strong flow, the river may cut through the neck and take a straighter route. The abandoned curved loop can then become an oxbow lake. Option A, desert formation, is not the characteristic result of a meander. Option B is correct because it is the classic cut-off bend feature. Option C, glacier formation, needs long-lasting ice and suitable cold conditions. Option D, volcano formation, is related to volcanic activity, not river bends. Memory cue: meander cut off = oxbow lake.

Correct answer: A. Deposition of sediments at the river mouth

A river may form a delta by depositing its load where it meets a sea or lake. In exams treat delta as a depositional landform.

Correct answer: A. They add water and sediments to the main river

Tributaries increase the water and material of the main river. In exams remember tributaries as branches of a river system.

Correct answer: A. Crop production can increase on cultivable land

River water can support irrigation and increase agricultural production. In exams write irrigation as an economic use of rivers.

Correct answer: A. Because of water fertile soil and transport facilities

River valleys are suitable for life agriculture and movement. In exams understand river valley civilizations on this basis.

Correct answer: A. The flow can be controlled and stored

Dams store river water and can release it in a controlled way. In exams link dams with irrigation and hydropower.

Correct answer: A. On aquatic life and water quality

Polluted water affects both fish and human use. In exams write pollution control under river conservation.

Correct answer: B. Erosion

The direct answer is B: erosion. River erosion is the wearing away and removal of soil, rocks, or land by moving water. A river has energy because it flows, and this energy can scrape, break, carry, and cut material from its banks and bed. Step by step, flowing water strikes the land, loosens particles, carries some of them away, and may deepen or widen a valley. Therefore, the action described as a river cutting land is erosion. Option A, deposition, is the opposite process: it is the laying down of material when the river loses energy. Option B is correct because cutting and wearing away are the meanings of erosion. Option C, evaporation, is the change of liquid water into water vapour due to heat; it does not describe cutting land. Option D, condensation, is the change of water vapour into liquid water; it also has no connection with river cutting. Exam cue: erosion removes material, while deposition leaves material behind.

Correct answer: A. Sufficient depth and regular water flow

Navigation needs river depth and continuity of water. In exams consider water transport as a use of rivers.

Correct answer: A. Soil fertility increases

Alluvial soil contains nutrients so fields become fertile. In exams link river plains with agricultural regions.

Correct answer: A. Separating two drainage basins

A water divide forms the boundary between different river basins. In exams remember it as the boundary of a drainage basin.

Correct answer: A. Carrying water from land to sea lake or another river

Rivers move surface water forward and keep the water cycle active. In exams treat rivers as the flowing link of the water cycle.

Correct answer: A. During floods the river deposits coarse sediments near its banks

During floods heavier particles deposit quickly near river banks and form levees. In exams link natural levees with flood deposition.

Correct answer: A. The slope is moderate and the river may meander

In the middle course a river cuts banks and also deposits some material. In exams link the middle course with meanders.

Correct answer: A. Erosion transportation and deposition

Direct answer: Option A, erosion, transportation, and deposition. A river first erodes or cuts soil and rock, then transports the loosened material as its load, and finally deposits it when its speed or carrying power decreases. These are the three major geographical actions of running water. A is correct because it gives the complete river process. B describes parts of the water cycle, not the main geomorphic work of a river. C lists natural hazards, not ordinary river actions. D lists forms of energy or physical phenomena and is unrelated to river landform development. The order is useful: cut, carry, and deposit. Memory cue: a river “cuts, carries, and creates” through deposition.

Correct answer: A. They are suitable for farming settlement and transport

River plains are flat and fertile so economic activities grow. In exams link river plains with agriculture and settlements.

Correct answer: A. River depth may decrease and flood risk may increase

Silt is fine material such as soil, clay, and very small mineral particles carried by flowing water. When too much silt settles in a river channel, the channel may become shallower and its capacity to carry water can decrease. During heavy rain or high flow, water may then overflow the banks more easily, increasing flood risk in nearby areas. The exact effect depends on the river, flow, and management conditions, so the result is a possible consequence rather than an unavoidable one.

Option A is correct because it states that river depth may decrease and flood danger may increase. A river does not always become deeper from silt deposition; pollution does not end because of silt, and a river’s source does not become a sea. The supplied explanation correctly connects siltation with reduced carrying capacity and possible flooding. Therefore the supplied answer A is accurate.

Correct answer: A. Because the river velocity decreases

When slope decreases flow energy reduces so deposition increases. In exams remember the relation among slope velocity and deposition.

Correct answer: A. Tributaries join the main river and increase its flow

Tributaries make the river system wider. In exams connect the term tributary with the main river.

Correct answer: A. They provide habitat to aquatic life and riparian vegetation

Fish plants and many organisms live in river systems. In exams understand a river also as an ecosystem.