Multiple Choice Questions

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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.


C.

If assertion is true but reason is false

The process of transfer of energy from producers through a series of organisms i.e. from primary consumers to secondary consumers to tertiary consumers by process of eating and being eaten constitute a food chain, eg. grassland ecosystem. Food chains can never occur independently in ecosystem but various food chains are inter-connected with each other forming an interlocked system known as food web. In grassland ecosystem food chains may be-

(i)Grass > Rabbit > Hawk/kite

(ii)Grass > Mouse > Snake > Kite/Hawk

(iii)Grass > Grasshopper > Lizard > Kite/Hawk

So, the food web will include kite.


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Plants of which one of the following groups of genera arc pollinated by the same agency

  • Triticum, Cocos, Mangifera

  • Ficus, Kigelia, Casuarina

  • Salvia, Morus, Euphorbia

  • Bombax, Butea, Bauhinia


The Montreal Protocol refers to

  • persistent organic pollutants

  • global warming and climate change

  • substances that deplete the ozone layer

  • biosafety of genetically modified organisms.


Keystone species deserve protection because these

  • are capable of surviving in harsh environmental conditions

  • indicate presence of certain minerals in the soil

  • have become rare clue to overexploitation

  • play an important role in supporting other species.


In India, we find mangoes with different flavours, colours, fibre content, sugar content and even shelf-life. The large variation is on account of

  • species diversity

  • induced mutations

  • genetic diversity 

  • hybridisation


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During protein synthesis in an organism at one point the process comes to a halt. Select the group of the three codons from the following, from which any one of the three could bring about this halt.

  • UUU, UCC, UAU

  • UUC, UUA, UAC

  • UAG, UGA, UAA 

  • UUG, UCA, UCG     


Biosphere reserves differ from National Parks and Wildlife sanctuaries because in the former

  • human beings are not allowed to enter

  • people are an integral part of the system

  • plants are paid greater attention than the animals

  • living organisms are brought from all over the world and preserved for posterity.


Somaclonal variation is seen in

  • tissue culture grown plants

  • apomiets

  • polyploids

  • vegetatively propagated plants.


Assertion: A person who has received a cut and is bleeding needs to be given anti-tetanus treatment.

Reason: Anti-tetanus injection provides immunity by producing antibodies for tetanus.

  • 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: Cancer cells are virtually immortal until the body in which they reside dies.

Reason: Cancer is caused by damage to genes regulating the cell division cycle.

  • 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.