Ecosystem

Assertion : In a food chain members of successive higher levels are fewer in number.

Reason : Number of organisms at any trophic level depends upon the availability of organisms which serve as food at the lower level.

• If both Assertion and Reason are true and the reason is the correct explanation of the assertion

• If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

• If Assertion is true statement but Reason is false

• If both Assertion and Reason are false statements

Biological Oxygen Demand (BOD) is a measure of

• industrial wastes poured into water bodies

• extent to which water is polluted with organic compounds

• amount of carbon monoxide inseparably combined with haemoglobin

• amount of oxygen needed by green plants during night

When a natural predator (living being) is applied on the other pathogen organism to control them, this process is called

• biological control

• genetic engineering

• artificial control

• confusion technique

The food chain starts from :

• consumer

• producer

• decomposer

• nitrogen fixation

Enzyme and carbohydrates dominate in the digestive tract of

• carnivores

• omnivores

• parasites

• herbivores

The 10% energy transfer law of food chain was given by

• Stanley

• Weismann

• Lindemann

• Tansley

The term 'ecosystem' was coined by :

• E.P. Odum

• A.G. Tansley

• Carl Mobious

• W. Clementus

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

• increases

• become irregular

• remain constant

• decreases

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

July 11 is observed as:

• World population day

• No tobacco day

• World environment day

• World health day