Rain is called acid-rain when its pH is below
(1) 7

(2) 6.5

(3) 6

(4) 5.6.

In vehicles, catalytic converters are used

(1) to increase mileage of vehicles

(2) to convert CO₂ into carbonates

(3) to increase the efficiency of lead mixed petrol

(4) to convert CO to CO₂.

Which of the following statements is correct ?
(1) Electrostatic precipitator can separate particulate matter of diameter less than 2.5 micrometers.

(2) Histones are acidic in nature that forms core for DNA packaging

(3) Lactobacillus is not present in dough used in idli formation.

(4) Template with polarity 5' $\to$3' has continuous DNA replication.

Cattle ranches are known to causes acute green house effect. This is due to
(1) mechanized milking practices

(2) methanogenic bacteria in rumen

(3) decomposition of left over fodder

(4) decomposition of organic remains in faeces.

Select the correct statement.

(1) Particulate matter of size 10 μm can create severe damage to the lungs.

(2) Particulate matter of size greater than 2.5 $\mathrm{\mu }$m can get trapped in lungs and cause problems.

(3) Particulate matter of size less than 2.5 μm penetrate deep into lungs.

(4) None of the above.

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.

(1) (i), (ii) and (iii)

(2) (i), (ii) and (iv)

(3) (ii) and (iii)

(4) (iii) and (iv)

Which of the following is a secondary pollutant?

(1) Carbon dioxide

(2) Nitrogen oxides

(3) Peroxyacyl nitrates

(4) All of these

Match teh following and select the correct option.

(1) A - (iii), B - (ii), C - (iv), D - (i)

(2) A - (ii), B - (iii), C - (iv), D - (i)

(3) A - (i), B - (iii), C - (ii), D - (iv)

(4) A - (iv), B - (ii), C - (iii), D - (i)

One greenhouse gas contributes 14% to total global warming and another contributes 6%. These are respectively identified as 
(1) N₂O and CO₂

(2) CFCs and N₂O

(3) methane and CO₂

(4) methane and CFCs

Which one option is incorrectly matched regarding biological magnification of DDT in aquatic ecosystem.
(1) Small fish                        0.5 ppm 

(2) Large fish                        2 ppm

(3) Fish eating birds               25ppm

(4) Zoopkankton                   0.003 ppm