Lakes

Correct answer: B. Providing water for irrigation

Water from some lakes can be used for irrigation. Exam tip: remember lakes as a source of irrigation.

Correct answer: C. A lake may be still water while a river is a flowing stream

A lake is generally a still water body while a river is flowing water. Exam tip: remember still and flowing water difference.

Correct answer: D. Because evaporation leaves salts behind

Direct answer: D, because evaporation leaves salts behind. Water in a lake can evaporate under heat, while dissolved salts generally do not evaporate with the water. Step by step, water enters the lake carrying small amounts of dissolved minerals; sunlight and dry conditions remove some water as vapour; the salts remain in the lake; if evaporation continues and fresh water does not dilute it, the salt concentration rises. Option A is wrong because the presence or absence of fish does not explain salinity. Option B is wrong because salt lakes are not necessarily glacial. Option C is the opposite of the real process: evaporation does occur and is an important cause. Memory cue: “Water goes up as vapour; salt stays down.”

Correct answer: A. Lagoon

A lagoon is a shallow water body partly separated from the sea. Exam tip: connect lagoon with coastal lakes.

Correct answer: B. They provide water and habitat for fish culture

Lakes provide suitable habitat and water for fish. Exam tip: add fisheries among uses of lakes.

Correct answer: C. Entry of dirty water and waste

Dirty water and waste can pollute lakes. Exam tip: study causes of pollution with conservation measures.

Correct answer: D. It decreases

Siltation reduces a lake's depth and storage capacity. Exam tip: link siltation with reduced capacity.

Correct answer: A. Because they make scenery and surroundings attractive

Lakes enhance scenery and tourist attraction. Exam tip: connect natural beauty with tourism value.

Correct answer: B. Seasonal lake

The direct answer is B: a seasonal lake. A seasonal lake contains water mainly during a particular season, usually after rainfall, and may shrink greatly or become dry during the dry season. Its water level depends strongly on seasonal rain, inflow, evaporation, and sometimes groundwater. Option A, permanent lake, is wrong because a permanent lake normally retains water throughout the year, although its level may rise or fall. Option B is correct because “seasonal” means occurring or lasting only during certain seasons. Option C, deep lake, is wrong because depth describes how deep a lake is; it does not by itself mean that the lake lacks water for part of the year. A deep lake can be permanent. Option D, coastal lake, is wrong because coastal describes location near the sea, not whether water remains all year. A coastal lake may be permanent or seasonal. The key distinction is duration of water storage, not depth or location. Memory cue: seasonal water comes with the season and may disappear after the rains end.

Correct answer: C. They may release water slowly and maintain flow

Lakes can release stored water slowly and help maintain flow. Exam tip: connect lakes with flow regulation.

Correct answer: A. Because water and resources are available there

People may settle near lakes due to water availability. Exam tip: remember the relation between water sources and settlements.

Correct answer: B. Stopping and treating dirty water

Stopping and treating dirty water is a good lake conservation measure. Exam tip: connect pollution control with conservation.

Correct answer: C. Loktak Lake

Loktak Lake in Manipur is famous for floating phumdis. Exam tip: remember Loktak with floating islands.

Correct answer: A. When water storage and height difference are available

Reservoirs and height difference can help in hydroelectric generation. Exam tip: connect water storage with hydropower.

Correct answer: A. Because lakes are stores of water

Lakes are important sources of water storage. Exam tip: remember lakes as examples of water resources.

Correct answer: A. Due to high evaporation

In semi-arid regions high evaporation can reduce water. Exam tip: remember dryness and evaporation together.

Correct answer: B. Aquatic life

Polluted water harms fish and other aquatic organisms. Exam tip: connect water quality with aquatic life.

Correct answer: A. Because activities like boating and picnics can occur there

Activities like boating and visits occur near lakes. Exam tip: connect recreation with human use of lakes.

Correct answer: B. Coastal barriers and lagoons

Coastal lakes are often separated from the sea by sand or barriers. Exam tip: remember the link between coastal lakes and lagoons.

Correct answer: C. May increase

Direct answer: Option C is correct. A lake stores water in a natural or artificial basin, so its water level can change when water enters or leaves it. After rainfall, water may flow directly into the lake or reach it through small streams and groundwater. This can increase the lake level, although the exact change depends on rainfall, drainage, evaporation and human use. Option A is wrong because rainfall does not make every lake empty; it generally adds water. Option B is wrong because ordinary rainfall does not always turn lake water into salt. Some lakes may become salty under special conditions, but that is not the normal result of rainfall. Option C is correct because the level may increase after rain. The word “may” is important: the rise is possible, not guaranteed to be identical everywhere. Option D is wrong because lake levels do change with rainfall, evaporation, inflow, outflow and water use. Exam cue: rain usually raises available surface water, while evaporation usually lowers it.

Correct answer: A. They help understand water bodies and drainage

Lakes are important for identifying water bodies on maps. Exam tip: remember locations of major lakes on maps.

Correct answer: B. Tourism and water supply

Lakes can help in both tourism and water supply. Exam tip: remember the multiple benefits of lakes.

Correct answer: A. Availability of water

Availability of water near a lake supports plant growth. Exam tip: connect water availability with vegetation.

Correct answer: A. Water and organisms will be polluted

Plastic waste harms water and aquatic organisms. Exam tip: connect plastic pollution with lake conservation.

Correct answer: B. It may be linked with coast and salinity

Coastal lakes are linked with the coast and sometimes saline or brackish water. Exam tip: use coastal location as an identification clue.