Eutrophication of water bodies leading to killing of fishes is mainly due to non-availability of 

• food

• light

• essential minerals

• essential minerals

In an area where DDT had been used extensively, the population of birds declined significantly because

• birds stopped laying eggs

• earthworms in the area got eradicated

• cobras were feeding exclusively on birds

• cobras were feeding exclusively on birds

Which one of the following is a wrong statement

• Most of the forests have been lost in tropical areas

• Ozone in upper part of atmosphere is harmful to animals

• Greenhouse effect is a natural Phenomenon

• Greenhouse effect is a natural Phenomenon

Measuring Biochemical Oxygen Demand (BOD) is a method used for

• Estimating the amount of organic matter in sewage water

• Working out the efficiency of oil driven automobile engines

• Measuring the activity of Saccharomyces cerevisae in producing curd on a commercial scale

• Measuring the activity of Saccharomyces cerevisae in producing curd on a commercial scale

15.

The zone of atmosphere in which the ozone layer is present is called 

• ionosphere

• mesophere

• stratosphere

• stratosphere

The organisation which publishes the Red List of species is

• ICFRE

• IUCN

• UNEP

• UNEP

A scrubber in the exhaust of a chemical industrial plant removes

• Gases like sulphur dioxide

• Particulate matter of the size 5 micrometre or above

• Gases like ozone and methane

• Gases like ozone and methane

The domestic sewage in large cities

• has a high BOD as it contains both aerobic and anaerobic bacteria

• is processed by aerobic and then anaerobic bacteria in the secondary treatment is Sewage Treatment Plants (STPs)

• When treated in STPs does not really require the aeration step as the sewage contains adequate adequate oxygen

• When treated in STPs does not really require the aeration step as the sewage contains adequate adequate oxygen

The UN Conference of Parties on climate change in the year 2011 was held in

• Poland

• South Africa

• Peru

• Peru

High value of BOD (Biochemical Oxygen Demand) indicates that

• water is pure

• water is highly polluted

• water is less polluted

• water is less polluted