Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

71.

If decomposers are removed what will happen to the ecosystem?

  • Energy cycle is stopped

  • Mineral cycle is stopped

  • Consumers cannot absorb solar energy

  • Rate of decompostion of mineral increases


72.

Which of the following is used as green manure?

  • Azolla

  • Azadirachta

  • Crotolaria juncea

  • Hevea brassiliansis


73.

Among plants "pheromones" are secreted by the cells of the following plants for given function

  • all plants for growth and development

  • Yeast for facilitating mating

  • all fungi for sexual reproduction

  • Rhizopus for formation of zygospore


74.

The gases that produce green house gases are

  • CH4, CFCs, CO2

  • CO2, N2O, H2

  • CFCs, NO2, O2

  • CO2, N2, water vapour


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75.

What's the difference between RNA and DNA?

  • Base

  • Sugar

  • Sugar and base

  • Phosphate


76.

Increase in toxic concentration from one trophic level to another trophic level is called

  • ecological toxification

  • bio- magnification

  • bioconcentration

  • cytological effect


77.

Which of the following workers are related as ecologist, palaeobotanist and embryologist respectively?

  • B. Salmi, R. Mishra, P. Maheshwari

  • R Mishra, B. Sahni, P. Maheshwari

  • B. Sahni, P. Maheshwari, R Mishra

  • P. Maheshwari, R Mishra, B. Sahni


78.

The Triticale is an intergeneric hybrid between

  • wheat and maize

  • maize and rye

  • wheat and rye

  • bajra and wheat


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79.

For the formation of tetrasporic embryosac, how many megaspore mother cells are required?

  • 1

  • 2

  • 3

  • 4


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80.

DNA replication generally proceeds in a 

  • 3 direction

  • 5 direction

  • 3 direction

  • 5 direction


A.

3 direction

DNA is made up of double helix of two complementary strands. Both the strands get seperated during replication. Each strand of the original DNA molecule then serves as a template for the production of its counterpart, hence, a process is known as semi- conservative replication.

DNA synthesis or replication always proceeds in 5' 3' direction because DNA polymerase acts on the 3'- OH of the existing strand for adding the free nucleotides.


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