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.
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
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
The production and maturation of sperm in testes is known as :
oogenesis
sporogenesis
gametogenesis
spermatogenesis
