Assertion: In tropical rain forests, O-horizon and A-horizon of s

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 Multiple Choice QuestionsMultiple Choice Questions

91.

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


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92.

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.


B.

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

A cross section of well developed soil shows more or less distinct layers called horizons.

0- horizon is the topmost layer of soil and A-horizon comes below O horizon. In the topmost layer, vegetation grows and various biological activities takes place. Tropical rain forests are found in tropical zone of the world and are characterized by very high temperature and abundance of rainfall. Soil in these area arc red latosols and are exceedingly thick. Leaching of minerals from the top soil occurs rapidly but cycling of nutrients also occur here. The laterite soils arc generally infertile because of intensive leaching and not due to growth of micro-organism.


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93.

July 11 is observed as:

  • World population day

  • No tobacco day

  • World environment day

  • World health day


94.

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


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95.

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


96.

The driving force of an ecosystem is :

  • producers

  • biomass

  • solar energy

  • grassland


97.

Acid rain is due to increase in atmospheric concentration of :

  • Ozone

  • CO2 and CO

  • SO3 and CO

  • SO2 and nitrogen oxide


98.

Which of the following factor is biotic

  • Photoperiod

  • CO2 content to the soil

  • Texture and porosity of soil

  • Rainfall


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99.

The pyramid of energy-in a forest ecosystem is

  • always upright

  • always inverted

  • both (a) and (b)

  • none of the above


100.

Identify which one of the following is an example, of incomplete ecosystem?

  • Grassland

  • Cave

  • River

  • Wetland


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