Living in same habitat organisms of same species from:

• biosphere

• community

• population

• niche

By anaerobic process, the cow dung is used to produce :

• methane

• butane

• ethane

• propane

As insecticides reach at higher trophic level in food chain their concentration :

• increases

• become irregular

• remain constant

• decreases

The term 'ecosystem' was coined by :

• E.P. Odum

• A.G. Tansley

• Carl Mobious

• W. Clementus

The food chain starts from :

• consumer

• producer

• decomposer

• nitrogen fixation

Some students, during a study, caught, marked and released 80 fishes in a pond. Later 100 fishes were caught at random. Among these 40 were found to be marked. What is the approximate number of fishes in the pond?

• 50

• 100

• 200

• 4000

The breakdown of detritus into small particles by detritivores is called

• Leaching

• Humification

• Catabolism

• Mineralization

• Mineralization

228.

Which of the following statements about Productivity is true?

• Primary productivity of all ecosystems is a constant

• The annual net primary productivity of the whole of the biosphere is 17 billion tons (dry weight) of organic matter

• Net primary productivity is the amount of biomass available for consumption by carnivores

• Secondary productivity is defined as the rate of formation of new organic matter by decomposers .

• Secondary productivity is defined as the rate of formation of new organic matter by decomposers .

The pioneer species in Xerarch and Hydrarch succession are respectively

• Lichens and sedges

• Lichens and rooted hydrophytes

• Phytoplanktons and lichens

• Lichens and phytoplanktons

• Lichens and phytoplanktons

According to Robert Constanza, 50% of the total cost for ecosystem services goes to

• Recreation

• Soil formation

• Nutrient cycling

• Climate regulation

• Climate regulation