Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

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81.

Photochemical smog formed in congested metropolitan cities mainly consists of:

  • Hydrocarbons, ozone and SOx

  • Hydrocarbons, SO2 and CO2

  • Smoke, peroxyacetyl nitrate and SO2

  • Ozone, peroxyacetyl nitrate and NOx


D.

Ozone, peroxyacetyl nitrate and NOx

Photochemical smog is a haze in the atmosphere accompained by high levels of ozone and nitrogen oxides, caused by the action of sunlight on pollutants. It consists of ozone, oxides of nitrogens, peroxiacetyl nitrate and various hydrocarbons (i. e., NOx). These are extermely complex in nature. It is mainly formed by UV rays reaction on primary pollutant. The oxidant formed in largest concentration is ozone, which is a serious pollutant in the lower atmosphere.


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82.

Acid rain is due to increase in atmospheric concentration of :

  • Ozone

  • CO2 and CO

  • SO3 and CO

  • SO2 and nitrogen oxide


83.

The true statement about 'green-house effect' is that it is caused by :

  • CO2 only

  • SO2 only

  • CO2 and SO2

  • CO2, CFC, CH4 and NO2 gases


84.

The first transgenic crop was :

  • pea

  • flax

  • tobacco

  • cotton


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85.

One of the major difficulties in the biological control of insect pests is the :

  • practical difficulty of introducing the predator to specific areas

  • method is less effective as compared with the use of insecticides

  • predator does not always survive when transferred to a new environment

  • predator develops a preference to other diets and may itself become a pest


86.

Secretion of androgens by testes is regulated by:

  • LTH

  • FSH

  • ICSH

  • Oxytocin


87.

The formation of gametophyte, from sporophyte, without spore formation or without meiosis is known as :

  • apospory

  • apogamy

  • parthenogenesis

  • none of these


88.

Anemophillous flowers have :

  • sessile stigma

  • small and smooth stigma

  • coloured flower

  • large and feathery stigma


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89.

During a woman's life time, she produces about:

  • 40-50 eggs

  • 300-350 eggs

  • 400-500 eggs

  • 750-850 eggs


90.

The production and maturation of sperm in testes is known as :

  • oogenesis

  • sporogenesis

  • gametogenesis

  • spermatogenesis


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