Multiple Choice Questions

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Assertion: Inbreeding increases homozygosity, thus exposes harmful recessive genes, which are eliminated by selection.

Reason: Continued inbreeding reduces fertility and productivity.

  • 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


B.

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

When the offsprings are produced by self fertilization or breeding between closely related parents it is called inbreeding. Inbreeding results in increase in homozygosity. The most revealing impact of inbreeding is the loss of vigour and physiological efficiency of the organisms characterized by reduction in size. A number of lethal and defective characters appear in the population which has undergone inbreeding (selfing). This loss of fitness in the progenies or decline in character expression with decreased heterozygosity arising from self mating is known as inbreeding depression or inbreeding decline. Continued inbreeding reduces fertility and even productivity. But the inbreeding progeny with lethal and harmful recessive genes being homozygous express these traits which otherwise remain hidden in heterozygous individuals. Natural selection works upon these individuals and eliminate them. Gradually, such genes get eliminated from the population.


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RNA interference is essential for the

  • cell proliferation

  • cell defence

  • cell differentiation

  • micropropagation


Assertion: There are 34 biodiversity hotspots in the world.

Reason: High level of species richness is a criteria for selection of a biodiversity hotspot.

  • 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


Assertion: Some marine animals find it difficult to live in fresh water and vice versa.

Reason: Some animals can tolerate a narrow salinity range, while others can tolerate a wide salinity range.

  • 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


Assertion: Hbs Hbs denotes the homozygous condition for sickle-cell anaemia.

Reason: It occurs due to substitution of glutamic acid by valine at the 6 position of (B-chain of Hb.

  • 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: 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


Assertion: Filarial worm is transmitted to humans by Culex mosquito.

Reason: Culex prefers to breed in fresh water.

  • 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.


Assertion: AIDS is caused by the HIV, a retro-virus.

Reason: Retroviruses have RNA genome.

  • 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.


Assertion: A male is found to be lacking facial hair and pubic hair.

Reason: It is a case of hyposecretion of testosterone from Leydig's cells of testes.

  • 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: Extra oxygen consumption in human, body is known as oxygen debt.

Reason: The extra oxygen is required by the body to oxidise the accumulated lactic acid produced during strenuous exercise.

  • 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.