Multiple Choice QuestionsCattle ranches are known to causes acute green house effect. This is due to
mechanized milking practices
methanogenic bacteria in rumen
decomposition of left over fodder
decomposition of organic remains in faeces.
A large quantity of urban sewage is drained to nearby village river. Which among the given conditions would happen after mixing of sewage into the river?
(i) Biochemical oxygen demand (BOD) of receiving water body increases.
(ii) Dissolved oxygen of receiving water body decreases.
(iii) It will not cause mortality among fishes and other aquatic creatures.
(iv) It will lead to nutrient enrichment of receiving water body.
(i), (ii) and (iii)
(i), (ii) and (iv)
(ii) and (iii)
(iii) and (iv)
B.
(i), (ii) and (iv)
Sewage having biodegradable organic matter is released into water body, micro- organisms involved in biodegradation consumes lot of oxygen to decompose the sewage. This results in a sharp decline in dissolved oxygen downstream from the point of sewage discharge and hence increases biological oxygen demand (BOD).
Presence of large amount of nutrients in water causes excessive growth of planktonic algae known as algal bloom. It causes deterioration of water quality and fish mortality.
Which of the following is a secondary pollutant?
Carbon dioxide
Nitrogen oxides
Peroxyacyl nitrates
All of these
Assertion : Presence of large amounts of nutrients in water body causes excessive growth of planktonic algae.
Reason : It is due to biomagnification.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
In vehicles, catalytic converters are used
to increase mileage of vehicles
to convert CO2 into carbonates
to increase the efficiency of lead mixed petrol
to convert CO to CO2
Assertion: Amount of organic biodegradable compounds present in water is measured by the BOD of that water.
Reason: During biodegradation of biodegradable organic compounds, oxygen is released by bacteria
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion: Algal blooms are formed in nutrientless water.
Reason: Algal blooms in water turn it unfit for human consumption, but cause enormous growth of fish.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this
Lots of urea and phosphate fertilizer were used in the vicinity.
The area was sprayed with DDT by an aircraft.
The lake water turned green and stinky.
Phytoplankton populations in the lake declined initially thereby greatly reducing photosynthesis.
Assertion: Dimethyl mercury is a highly persistent pollutant that accumulates in food chains.
Reason: Mercury pollution is responsible for minamata.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
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