Multiple Choice Questions

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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.


D.

the end of food chain and are decomposers.

Bacteria attacking the dead animals represent the end of the food chain and are decomposers. These are the organisms that obtain energy from chemical breakdown of organisms. They secrete enzymes onto dead matter and then absorb the breakdown products. Bacteria are specialised to breakdown organic materials that are difficult for other organisms to digest. They also fulfil a vital role in the ecosystem, returning the constituents of organic matter to the environment in inorganic forms so that they can again be assimilated by producers.


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Rain is called acid - rain when its pH is below

  • 7

  • 6.5

  • 6

  • 5.6


What is the Greek word for ecology?

  • Ethology

  • Oekologie

  • Synecology

  • Hexicology


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


What is PAR range?

  • 200 nm - 800 nm

  • 400 nm - 700 nm

  • 350 nm - 550 nm

  • 600 nm - 100 nm


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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.


Most animals that live in deep oceanic waters are

  • tertiary consumers

  • detritivores

  • primary consumers

  • secondary consumers


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


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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


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