Multiple Choice QuestionsPhotochemical 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
Acid rain is due to increase in atmospheric concentration of :
Ozone
CO2 and CO
SO3 and CO
SO2 and nitrogen oxide
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
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
D.
predator develops a preference to other diets and may itself become a pest
Biological control refers to the use of living organisms like natural predators and parasites to reduce pest population and control diseases. They play an important role in controlling the plant pests like nematodes weeds, insects and mites. It helps in maintaining and balancing the plant species along with their natural enemies.
However they may become pest as they can develop a preference to other diets.
The formation of gametophyte, from sporophyte, without spore formation or without meiosis is known as :
apospory
apogamy
parthenogenesis
none of these
Anemophillous flowers have :
sessile stigma
small and smooth stigma
coloured flower
large and feathery stigma
During a woman's life time, she produces about:
40-50 eggs
300-350 eggs
400-500 eggs
750-850 eggs
The production and maturation of sperm in testes is known as :
oogenesis
sporogenesis
gametogenesis
spermatogenesis
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