Multiple Choice Questions

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Assertion : Secondary succession takes place in recently denuded area.

Reason : It is caused due to baring of an area.

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

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

  • If assertion is true but reason is false

  • If both assertion and reason are false


A.

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

Biotic or ecological succession is the formation of a series of biotic communities at the same site over a period of time one after the other, till a stable climax community develops over the area. It occurs generally in bare areas.

Primary succession takes place on a biological sterile soil less primary barren area.

Secondary succession takes place in a recently denuded area which still contains a lot of organic debris, remains and propagules of previous living organisms. The area has become bared due to destruction of the community previously present. The baring of an area can be caused due to forest fire, deforestation for wood, timber and habitat, overgrazing, landslides or earthquakes, excessive and repeated droughts, fallowing a cropland and repeated floods.


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What is PAR range?

  • 200 nm - 800 nm

  • 400 nm - 700 nm

  • 350 nm - 550 nm

  • 600 nm - 100 nm


Which one of the following correctly represents an organism and its ecological niche?

  • Vallisneria and pond

  • Desert locust (Scistocerca) and desert

  • Plant lice (aphids) and leaf

  • Vultures and dense forest


Assertion: The plant biomass which serves as the food of herbivores and decomposers is said to result from the gross primary productivity.

Reason: Gross primary productivity is the rate of net production of organic material (biomass).

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

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

  • If assertion is true but reason is false

  • If both assertion and reason are false


What is the Greek word for ecology?

  • Ethology

  • Oekologie

  • Synecology

  • Hexicology


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The bacteria which attack dead animals are

  • first link of the food chain and are known as primary producers

  • second link of the food chain and are herbivorous

  • third link of the food chain and are tertiary consumers

  • the end of food chain and are decomposers.


Assertion: A network of food chains existing together in an ecosystem is known as a food web.

Reason: An animal like kite cannot be a part of a food web

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

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

  • If assertion is true but reason is false

  • If both assertion and reason are false.


Rain is called acid - rain when its pH is below

  • 7

  • 6.5

  • 6

  • 5.6


Assertion: In a terrestrial ecosystem, detritus food chain is the major conduit for energy flow.

Reason: Solar energy is the direct source for energy supply in a detritus food chain.

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

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

  • If assertion is true but reason is false.

  • If both assertion and reason are false


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Most animals that live in deep oceanic waters are

  • tertiary consumers

  • detritivores

  • primary consumers

  • secondary consumers


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