Biology : Ecosystem

What is PAR range?

• 200 nm - 800 nm

• 400 nm - 700 nm

• 350 nm - 550 nm

• 600 nm - 100 nm

Assertion: The plant biomass which serves as the food of herbivores and decomposers is said to result from the gross primary productivity.

Reason: Gross primary productivity is the rate of net production of organic material (biomass).

• 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: A network of food chains existing together in an ecosystem is known as a food web.

Reason: An animal like kite cannot be a part of a food web

• 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.

Which one of the following correctly represents an organism and its ecological niche?

• Vallisneria and pond

• Desert locust (Scistocerca) and desert

• Plant lice (aphids) and leaf

• Vultures and dense forest

Given below is one of the types pyramids.

This type represents

• pyramid of numbers in a grassland

• pyramid of biomass in a fallow land

• pyramid of biomass in a lake

• energy pyramid in a spring

Assertion: In tropical rain forests, O-horizon and A-horizon of soil profile are shallow and nutrient-poor.

Reason: Excessive growth of micro-organisms in the soil depletes its organic content.

• 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.

July 11 is observed as:

• World population day

• No tobacco day

• World environment day

• World health day

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

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

The driving force of an ecosystem is :

• producers

• biomass

• solar energy

• grassland