Tag: biology

Questions Related to biology

Read the given statements and select the correct option. 
Statement 1 : Bryophytes are amphibians of plant kingdom.
Statement 2 : They live in soil but depend on water for sexual reproduction.

biology pictorial feature of plant kingdom uses of bryophytes introduction to bryophytes cryptogams

  1. Both statements 1 and 2 are correct.

  2. Statement 1 is correct but statement 2 is incorrect.

  3. Statement 1 is incorrect but statement 2 is correct.

  4. Both statements 1 and 2 are incorrect.

Show answer
Correct Option: A
Explanation:

Bryophytes are known as 'amphibians of plant kingdom' because they are adapted to land as well as water habitats. In their vegetative structure, bryophytes have become adapted to land. But they depend on water for sexual reproduction because the swimming habit is retained by their sperms.

Which is the main causative factor of desertification

biology the soil soil erosion (geo) soil erosion, soil conservation and uses of soil soil erosion and conservation

  1. Developmental activities

  2. Tourism

  3. Overgrazing

  4. Irrigated agriculture

Show answer
Correct Option: C
Explanation:

Overgrazing is an important reason for desertification. Overgrazing denudes the soil of plant cover. Trampling by cattle decreases soil porosity. The exposed hardened soil undergoes erosion by wind and water. Wind erosion is more common, where drought conditions prevail for long periods. It causes desertification or conversion of once fertile land into desert.

Sheet erosion is caused by

biology the soil soil erosion (geo) soil erosion, soil conservation and uses of soil soil erosion and conservation

  1. Sea

  2. Wind

  3. Heavy rains

  4. Glaciers

Show answer
Correct Option: C
Explanation:

Sheet erosion means removal of extremely thin layer or sheet of soil. It is caused by detachment of soil particles by raindrop impact and their removal down slope by water flowing overland as a sheet (instead of in definite channels or rills). 

Loss of upper fertile layer of soil is known as

biology the soil soil erosion (geo) soil erosion, soil conservation and uses of soil soil erosion and conservation

  1. Pedogenesis

  2. Podosolization

  3. Soil erosion

  4. None of the above

Show answer
Correct Option: C
Explanation:

Soil erosion is removal of top soil by agency of water (water erosion) and wind (wind erosion). Soil erosion is of two types- natural and anthropogenic. 

Natural or geological erosion is extremely slow removal of top soil due to rain water or wind. 
Anthropogenic soil erosion is caused by removal of plant cover through over grazing, litter collection, tree felling, leaving the soil unprotected during agricultural operations.
Pedogenesis is the process of soil formation.
Podsol is base poor acidic soil formed by leaching of basic minerals. The process of formation of podsol is called as podsolization.

Soil erosion is greater when

biology the soil soil erosion (geo) soil erosion, soil conservation and uses of soil soil erosion and conservation

  1. There is no rain

  2. The rainfall is low

  3. Winds do not blow

  4. The rainfall is received in heavy downpour

Show answer
Correct Option: D
Explanation:

Soil erosion is removal of top soil by agency of water (water erosion) and wind (wind erosion). Soil erosion is of two types- natural and anthropogenic. 

Natural or geological erosion is extremely slow removal of top soil due to rain water or wind. 
Anthropogenic soil erosion is caused by removal of plant cover through over grazing, litter collection, tree felling, leaving the soil unprotected during agricultural operations. 
Anthropogenic factors remove green cover and expose the soil to natural agents of soil erosion i.e., water and wind. When rains fall as heavy downpour, most of the top layer of soil is washed away, if the soil is not covered by vegetation.

Sheet erosion is caused by

biology the soil soil erosion (geo) soil erosion, soil conservation and uses of soil soil erosion and conservation

  1. Fast running rivers

  2. Wind

  3. Heavy rains

  4. Glaciers

Show answer
Correct Option: C

Soil erosion is greater when

biology the soil soil erosion (geo) soil erosion, soil conservation and uses of soil soil erosion and conservation

  1. There is no rain

  2. The rainfall is low

  3. Winds do not blow

  4. The rainfall is received in heavy down pour

Show answer
Correct Option: D

Eroded soils are

biology the soil soil erosion (geo) soil erosion, soil conservation and uses of soil soil erosion and conservation

  1. Devoid of plant nutrients

  2. Richer in plant nutrients

  3. Unaltered in plant nutrients

  4. Fit for agriculture

Show answer
Correct Option: A
Explanation:

Soil erosion is the removal of top soil, top soil has all the nutrients necessary for plant growth. Eroded soil is low on fertility

So, the correct answer is 'Devoid of plant nutrients'

Soil erosion can be prevented by

biology the soil soil erosion (geo) soil erosion, soil conservation and uses of soil soil erosion and conservation

  1. Raising forests

  2. Deforestation

  3. Excessive use of fertilizer

  4. Overgrazing by animals

Show answer
Correct Option: A
Explanation:

Soil erosion is the process of washing and wearing away of the top fertile soil due to the physical pressure and force of water, wind or other farming activities like tilling, ploughing etc.
The soil can be prevented from getting eroded by planting and raising more trees as the roots of the trees hold the soil tightly and prevents it from getting washed away.
Deforestation means cutting down of trees and more we cut down the trees more the soil will be left loose and easily washed away and get eroded.
Excessive use of fertilizers can leave the soil degraded, loose, dry and barren and more vulnerable and easier to get eroded.
Overgrazing by animals can leave the soil loose, dry and barren totally exposed to get washed away and get eroded completely.

Siltation in rivers, harbors and reservoirs is caused by

biology the soil soil erosion (geo) soil erosion, soil conservation and uses of soil soil erosion and conservation

  1. Erosion

  2. Removal of topsoil

  3. Eutrophication

  4. Deforestation

Show answer
Correct Option: A