Multiple Choice Questions

Advertisement

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


A.

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

For aquatic organism salt concentration (measured as salinity in parts per thousand) is a major factor for their survival. Salinity of different aquatic habitats varies greatly. It is less than 5 per thousand parts, in inland waters, 30-35 per thousand parts in the sea and more than 100 per thousand parts in some hypersaline lagoons. Many fresh water animals cannot live for long in sea water and vice versa because of the osmotic problems they would face due to the change in relative tonicity of the surrounding water with cytoplasm. It may result into endosmosis or exosmosis according to the conditions. The tolerance of organisms to the salinity range varies. Some organisms are tolerant of a wide range of salinities and are called euryhaline e.g. salmon, while some can tolerate only a narrow range of salinity i.e., stenohaline e.g., shark


Advertisement

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: 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


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.


Advertisement

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.


Advertisement

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.