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Questions Related to evs

Layer of cells that secrete enamel of tooth is 

evs structure and functions of living organisms -ii experiments on digestive enzymes role of receptors in the mouth types of teeth introduction to human digestive system circulatory system and organs

  1. Osteoblast

  2. Ameloblast

  3. Odontoblast

  4. Dentoblast

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Correct Option: B
Explanation:

Osteoblast-bone forming cell. Ameloblast-enamel elaborating cell. Odontoblast- dentine elaborating cell. Dentoblast- tooth cell.

The teeth placed at the end of the buccal cavity and help in chewing food are which of the following?

evs structure and functions of living organisms -ii experiments on digestive enzymes role of receptors in the mouth types of teeth introduction to human digestive system circulatory system and organs

  1. Incisors

  2. Molars

  3. Canines

  4. Premolars

Show answer
Correct Option: B
Explanation:
The most posterior teeth in the mouth are the molars. They have broader and flatter surfaces with 4-5 cusps. They help in chewing and grinding the food.
So the correct answer is 'Molars'.

Plants remove carbon in the form of:

evs let's plant trees damaging the forests deforestation and afforestation protecting our environment pollution of soil degradation of land

  1. Carbonates

  2. Carbon monoxide

  3. Bicarbonates

  4. Carbon dioxide

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Correct Option: D
Explanation:

Plants remove carbon in the form of carbon dioxide from the atmosphere during the process of photosynthesis.

Which of the following provides nutrients to the seedlings to grow in forests?

evs let's plant trees damaging the forests deforestation and afforestation protecting our environment pollution of soil degradation of land

  1. Bacteria

  2. Fungi

  3. Decaying animal dung

  4. Beetles and grubs

Show answer
Correct Option: C
Explanation:

Animals living in the forest include herbivores and carnivores. The dung of these animals are decomposed by insects living in the soil. This contributes to the fertility of the soil by adding organic matter and nutrients, such as nitrogen, that is trapped by bacteria in the soil. This provides nutrients to the seedlings to grow in forests. Thus the correct answer is option C.

What is reforestation?

evs let's plant trees damaging the forests deforestation and afforestation protecting our environment pollution of soil degradation of land

  1. Cutting of trees.

  2. Restocking of the destroyed forests by planting new trees.

  3. Conversion of fertile soil into forest.

  4. Conversion of forest into fertile soil.

Show answer
Correct Option: B
Explanation:

Reforestation is restocking of the destroyed forest by planting new trees. We should plant at least as many trees as we cut. Reforestation can take place naturally also.

Thus, the correct answer is option B.

Deforestation is caused due to

evs let's plant trees damaging the forests deforestation and afforestation protecting our environment pollution of soil degradation of land

  1. grazing

  2. timber

  3. Cultivation

  4. all of these

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Correct Option: D

What is the effect of deforestation on amount of $CO _2$ in atmosphere?

evs let's plant trees damaging the forests deforestation and afforestation protecting our environment pollution of soil degradation of land

  1. It increases

  2. It decreases

  3. It remains unchanged

  4. Cannot be predicted

Show answer
Correct Option: A
Explanation:

Deforestation is the permanent destruction of forests in order to make the land available for other uses. Deforestation has many negative effects on the environment. The most dramatic impact is a loss of habitat for millions of species. Seventy percent of Earth's land animals and plants live in forests, and many cannot survive the deforestation that destroys their homes. Deforestation also drives climate change. Since, trees purify air by absorbing carbon dioxide from atmosphere, loss of trees would result into increase in level of carbon dioxide.

Deforestation refers to

evs let's plant trees damaging the forests deforestation and afforestation protecting our environment pollution of soil degradation of land

  1. planting of trees

  2. cultivation of crops

  3. disappearance of forests

  4. development of plantation

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Correct Option: C

Most fertile layer of soil is

evs let's plant trees damaging the forests deforestation and afforestation protecting our environment pollution of soil degradation of land

  1. top layer

  2. organic layer

  3. middle soil layer

  4. all of these

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Correct Option: A

Plants control the humidity in air by

evs let's plant trees damaging the forests deforestation and afforestation protecting our environment pollution of soil degradation of land

  1. Photosynthesis

  2. Transpiration

  3. Photorespiration

  4. All of the above

Show answer
Correct Option: B
Explanation:

Plants absorb water from the soil and looses it to the atmosphere by transpiration,hence,control the humidity in air by acting as a water exchanger between ground and atmosphere.