The nutrients in an ecosystem are:
1. | continuously lost from an ecosystem |
2. | needed as a continuous supply from the outside |
3. | recycled time and again indefinitely |
4. | continuously synthesized by physical forces |
Converting nitrate to nitrogen gas by anaerobes like Pseudomonas is:
1. | nitrogen fixation | 2. | ammonification |
3. | denitrification | 4. | eutrophication |
A chemical that enters living organisms primarily from the atmosphere is:
1. | phosphorus | 2. | sulfur |
3. | sodium | 4. | carbon |
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Assertion (A): | Of all the required nutrients other than nitrogen, phosphorus is the most likely to be scarce enough to limit plant growth. |
Reason (R): | The reservoir of phosphorus is in the mineral form rather than in the atmosphere. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
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The amount of carbon dioxide in the atmosphere is:
1. increasing
2. decreasing
3. holding steady
4. fluctuating wildly
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Assertion (A): | We generally undervalue the magnitude of ecosystem services that benefits us. |
Reason (R): | We do not attach a monetary value to the services of natural ecosystems. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
The prime driving force for the water cycle is:
1. | evapotranspiration from plants |
2. | rainfall |
3. | snowmelt |
4. | percolation of water through the soil |
Among the following bio-geo-chemical cycles, which one does not have losses due to respiration?
1. Phosphorus
2. Nitrogen
3. Sulphur
4. All of the above
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Consider the following statements:
I: | The atmosphere only contains about 1% of total global carbon. |
II: | Unlike the carbon cycle, there is no respiratory release of phosphorus into the atmosphere. |
III: | Sulphur and phosphorus cycles are sedimentary cycles. |
Which of the above statements are true?
1. I and II only
2. I and III only
3. II and III only
4. I, II, and III
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Consider the two statements:
I: | Phosphorus is much more important as a limiting nutrient in aquatic systems. |
II: | Phosphorus is generally much less soluble than nitrogen, it is leached from the soil at a much slower rate than nitrogen. |
1. Both I and II are correct and II explains I.
2. Both I and II are correct but II does not explain I.
3. I is correct and II is incorrect.
4. Both I and II are correct.