A chemical that enters living organisms primarily from the atmosphere is:

1.  phosphorus 2.  sulfur
3.  sodium 4.  carbon

Subtopic:  Mineral Cycling & Ecosystem Services (OLD NCERT) |
 81%
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What is the best description of trophic efficiency?

1.  the ratio of net secondary production to the assimilation of primary production.
2.  the percentage of production transferred from one trophic level to the next.
3.  a measure of how nutrients are cycled from one trophic level to the next.
4.  usually greater than production efficiencies.

Subtopic:  Ecosystem Productivity |
 62%

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Nitrogen fixation is carried out by:

1.  bacteria 2.  fungi
3.  protists 4.  algae

Subtopic:  Microbes as Biofertilizer |
 82%
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What percent of the energy fixed by primary producers in a typical field ecosystem is received by a secondary consumer?

1.0.1%2.1%
3.10%4.20%

Subtopic:  Energy Flow |

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The rate at which energy is converted by photosynthetic and chemosynthetic autotrophs to organic substances is called as:
1. biomass
2. transpiration
3. net primary productivity
4. gross primary productivity

Subtopic:  Ecosystem Productivity |
 66%

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The chemical energy that is not converted to new biomass in the process of energy transfer between trophic levels in an ecosystem is finally:
1. removed in the feces
2. recycled by decomposers
3. used by heterotrophs to thermoregulate.
4. dissipated into space as heat

Subtopic:  Energy Flow |
 55%

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The percent of the sun’s energy captured by plants is approximately:

 
1. 1% 2. 10%
3. 20% 4. 50%
Subtopic:  Energy Flow |
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Aquatic ecosystems that are most adversely affected by acid are those that lack:
1. calcium
2. carbonic acid
3. nitrate
4. bicarbonate

Subtopic:  Components & Types of Ecosystems |

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The largest net primary production of the Earth is contributed by:
1. savanna
2. salt marsh
3. open ocean
4. tropical rainforest

Subtopic:  Ecosystem Productivity |

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An example of primary succession would be:

1. Soil formation in the crater of an extinct volcano
2. Growth of a pine forest after a fire
3. Restoration of grass on a former agricultural field
4. Starfish colonizing on a coral reef

Subtopic:  Ecological Succession (OLD NCERT) |
 69%

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