Tag: evs

Questions Related to evs

The decomposers in the forest perform 

evs forests: our lifeline food material and source sources of food and food habits of animals seed dispersal

  1. Production of the plants

  2. Decomposition of the plants and animals

  3. Breakdown of the forests

  4. All of the above

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Correct Option: B
Explanation:

Decomposers are saprotrophs, which decompose the organic remains of plants and animals by secreting extracellular digestive enzymes. Due to degradation of organic remains, decomposers are also called reducers. Heterotrophic bacteria and saprophytic fungi are the important organisms which usually act as decomposers. Thus, the correct answer is option B.

Assertion : Interspecific hybridization often fails to form normal embryos.

Reason : Such embryos can germinate in culture conditions.

evs forests: our lifeline food material and source sources of food and food habits of animals seed dispersal

  1. If both assertion and reason are true and the reason is the correct explanation of the assertion.

  2. If both assertion and reason are true but reason is not the correct explanation of the assertion.

  3. If assertion is true but reason is false.

  4. If the assertion and reason both are false.

  5. If assertion is false but reason is true.

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Correct Option: B
Assertion:Methyl mercury highly persistent kind of pollutant that accumulates in food chain 
Reason: Mercury pollution is responsible for Minamata disease
evs forests: our lifeline food material and source sources of food and food habits of animals seed dispersal

  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion

  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion

  3. If the assertion is true but the reason is false

  4. If both the assertion and reason are false

  5. If the assertion is false but reason is true

Show answer
Correct Option: B

In grazer food chain the living plants are directly

evs forests: our lifeline food material and source sources of food and food habits of animals seed dispersal

  1. destroyed

  2. consumed

  3. decayed

  4. grown

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Correct Option: B

Which among the following always decreases in a Food chain across tropic levels?

evs forests: our lifeline food material and source sources of food and food habits of animals seed dispersal

  1. Number

  2. Accumulated chemicals

  3. Energy

  4. None of the above

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Correct Option: C

Which of the following helps in the formation of humus?

evs forests: our lifeline food material and source sources of food and food habits of animals seed dispersal

  1. Earthworm

  2. Lion

  3. Birds

  4. None of the above

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Correct Option: A

Which organism will be affected in the absence of the decomposers?

evs forests: our lifeline food material and source sources of food and food habits of animals seed dispersal

  1. Plants

  2. Animals

  3. Insects

  4. All of these

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Correct Option: D
Explanation:

Decomposers are the organisms that play a critical role by breaking down and decomposing the body and release the element back to nature for other organisms. Thus they help in recycling the nutrients in the atmosphere. They also act as the cleaning agent of the environment because without them dead organisms will pile up. Thus in their absence all the organisms i.e., plants, animals, and insects will be affected. Thus, the correct answer is option D.

Fill in the blanks:

According to Newton, different colors of light are due to the difference in _______ of the corpuscles.

evs light and shadow dual nature of light nature and sources of light theories on light

  1. mass

  2. nature

  3. shape

  4. size

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Correct Option: D
Explanation:

Corpuscles are single, infinitesimally small, particles which have shape, size, color, and other physical properties.

Light of wavelength $\lambda $ from a point source falls on a small circular obstacle of diameter d. Dark and bright circular rings around a central bright spot are formed on a screen beyond the obstacle. The distance between the screen and obstacle is D. Then , the condition for the formation of rings, is

evs light and shadow dual nature of light nature and sources of light theories on light

  1. $\sqrt { \lambda } \approx \cfrac { { d } }{ 4D } $

  2. $\lambda \approx \cfrac { { d }^{ 2 } }{ 4D } $

  3. $d\approx \cfrac { { \lambda }^{ 2 } }{ D } $

  4. $\lambda \approx \cfrac { D }{ 4 } $

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Correct Option: B

Which of the following is incorrect?

evs light and shadow dual nature of light nature and sources of light theories on light

  1. A thin convex lens of focal length ${f} _{1}$ is placed in contact with a thin concave lens of focal length ${f} _{2}$. The combination will act as convex lens if ${f} _{1}<{f} _{2}$

  2. Light on reflection at water-glass boundary will undergo a phase change of $\pi$

  3. Spherical aberration is minimized by achromatic lens

  4. If the image of distant object is formed in front of the retina then defect of vision may be myopia

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Correct Option: B