Primary treatment of sewage means
encouragement of growth of microbes to decompose sewage
disinfection of sewage
removal of heavy grit from sewage in the settling chambers
pumping of sewage into aeration tanks for increased microbial activity
Correct Answer :
C. removal of heavy grit from sewage in the settling chambers
Related Questions
In cities like Mumbai and Delhi, the major air pollutants are
ozone
carbon monoxide and oxides of sulphur
hydrocarbons and hot air
algae spores and marsh gas
. Biome is
the flora on land
the flora in ocean
a community of organisms interacting with each other
that part of earth and its atmosphere which inhabits living organisms
The best indicator of SO^2 pollution is
Lichens
Algae
Fungus
Fems
Water plants usually have
a well developed root system
a well developed vascular system
a well developed stomatal system
a reduced vascular system
Deforestation may reduce the chances of
frequent cyclones
rainfall
frequent landslides
erosion of soil surface
Vegetation in Delhi is predominantly
halophytic
mesophytic
xerophytic
hydrophytic
The ultimate source of energy for fish is
Protozoa
Oxygen produced by plants
Sunlight
Manure in the soil
Commensalism is
when both organisms are benefited
when one organism is benefited without affecting the other
when one organism is affected
when both organisms are affected
Increasing accumulation of DDT in organisms of a food chain in higher trophic levels is known as
biotic potential
biotic component
biological value
biological amplification
Hie earliest settlers on barren lands are generally
Diatoms
Lichens
Mosses
Ferns
The first stage of plant succession on earth is called
Adaptation
Acclimatisation
Colonisation
All the above
A pollutant is any substance, chemical or other factor that changes
natural geochemical cycles
the natural flora of a place
the natural wild life of a region
the natural balance of our environment
Which is the correct food chain
grass � wolf > deer > buffalo
bacteria � grass � rabbit > wolf
grass � insect � bird � snake
grass > snake �insect � deer
Correct definition of ecosystem is :
A community of organisms interacting with one another
The abiotic component of a habitat
The part of the earth and its atmosphere which inhabits living organisms
The community of organisms together with environment in which they live
The biggest herbarium of India is
Botanical Survey of India - Calcutta
St. Xavier's Herbarium - Mumbai
Central National Herbarium - Calcutta
IARI - New Delhi
In grassland ecosystem the pyramid of energy is
upright
inverted
upright or inverted
none of these
Competition for food, light and space is most severe in
closely related species growing in the same niche
closely related species growing in different habitats
distantly related species growing in same habitat
distantly related species growing in different habitats
Carbon cycle includes
producer - consumer - decomposer
decomposer - consumer - producer
producer - decomposer - consumer
consumer - producer - decomposer
The source of energy in the ecosystem is:
decomposition of animals and plants by bacteria
photosynthesis by green plants
fermentation of sugars
sun-light
Radiation is a health hazard as it causes
leukaemia
polio
pneumonia
haemophilia
A habitat of long severe winters and growing season limited to a few months of summer constitutes
Taiga ecosystem
Tundra ecosystem
Savannah ecosystem
Tropical rainforest
Biosphere is:
In which individuals interact with each other
In which life originated
The name of a bird
Organic compound by which life diminih
The least porous soil among the following is
loam soil
clay soil
sandy soil
poeaty soil
Laterization is a process which results in the
purification of water
formation of soil
sterilization of soil
degradation of soil
Which of the following functions performed by forests help most in controlling drought
Forest prevent soil erosion
Forests act as water sheds
Forests have lots of water plants
Forests bring rainfall, in monsoon
Hie sequence blue green algae > crustose lichens � foliose lichens > mosses � shrubs � dicotyledonous tree represents
a food chain
genetic drift
ecological succession trend
a phylogenetic trend
Autumn colouration of leaves appears only in
Tropical regions
Deserts
Temperate deciduous plants
Deserts
Humus is an example of
soil structure
organic colloids
crystalloids
none of the above
Desert plants are generally
Succulents
Heterophyllous
Herbaceous
Viviparous
When young plants are grazed too heavily they get killed because
the roots are starved
of the mechanical injury to roots
most of the aerial parts are eaten away
of the mechanical injury to branches