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Assertion (A): Coral reefs are generally absent on the Western coasts of continents 
Reason (R): Coral reefs do not flourish where there are cold currents 
Choose from the following options.
  • a)
    Both A and R are true and R is the correct explanation of A
  • b)
    Both A and R are true, but R is not a correct explanation of A
  • c)
    Both are false
  • d)
    A is false, but R is true
Correct answer is option 'A'. Can you explain this answer?
Most Upvoted Answer
Assertion (A): Coral reefs are generally absent on the Western coasts...
  • The water temperature must not fall 68°F. (20°C.). 
  • This virtually limits the areal distribution of corals to the tropical, and subtropical zones. 
  • Again they will not flourish where there are cold currents because of the cold water's upwelling from the depths that cools the warm surface water. 
  • This explains why coral reefs are generally absent on the western coasts of continents. 
  • On the other hand, the warming effect of the warm currents, e.g. the Gulf Stream, means that corals are found far to the north of the West Indies in the Atlantic Ocean. 
  • The Pacific and the Indian Oceans, however, have the most numerous coral reefs
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Assertion (A): Coral reefs are generally absent on the Western coasts...
Assertion (A): Coral reefs are generally absent on the Western coasts of continents

Reason (R): Coral reefs do not flourish where there are cold currents

The correct answer is option 'A', which means that both assertion (A) and reason (R) are true, and reason (R) is the correct explanation of assertion (A).

Explanation:

Coral reefs are marine ecosystems that are formed by the accumulation of the calcium carbonate skeletons of coral polyps. They are known for their high biodiversity and provide habitats for numerous marine species. However, coral reefs are generally absent on the Western coasts of continents due to various factors, and the reason behind this is the presence of cold currents.

1. Coral Reef Distribution:
Coral reefs are mainly found in tropical and subtropical regions, particularly in the Indo-Pacific and Caribbean regions. These regions have warm water temperatures and are located near the equator. The Western coasts of continents, on the other hand, often experience the influence of cold ocean currents.

2. Cold Currents and Coral Reefs:
Cold ocean currents have a significant impact on the distribution and growth of coral reefs. Cold water is generally not suitable for the growth and development of corals, as they are highly sensitive to temperature variations. The presence of cold currents lowers the water temperature, which inhibits the growth of coral reefs.

3. Upwelling and Cold Currents:
One of the reasons for the presence of cold currents along the Western coasts of continents is the phenomenon of upwelling. Upwelling occurs when cold, nutrient-rich waters from the deep ocean rise to the surface, replacing the warmer surface waters. These cold currents are often associated with upwelling zones and are important for the productivity of marine ecosystems.

4. Nutrient Availability:
While cold currents may not favor the growth of coral reefs directly, they do support the growth of other marine organisms such as phytoplankton. The nutrient-rich waters brought by cold currents promote the growth of phytoplankton, which forms the basis of the marine food chain. This, in turn, supports other marine organisms, including fish and marine mammals.

In conclusion, coral reefs are generally absent on the Western coasts of continents due to the presence of cold currents. These cold currents lower the water temperature, which is unfavorable for the growth and development of coral reefs. However, the presence of cold currents also contributes to the productivity of marine ecosystems by supporting the growth of other marine organisms.
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Assertion (A): Coral reefs are generally absent on the Western coasts of continents Reason (R): Coral reefs do not flourish where there are cold currents Choose from the following options.a) Both A and R are true and R is the correct explanation of Ab) Both A and R are true, but R is not a correct explanation of Ac) Both are falsed) A is false, but R is trueCorrect answer is option 'A'. Can you explain this answer?
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Assertion (A): Coral reefs are generally absent on the Western coasts of continents Reason (R): Coral reefs do not flourish where there are cold currents Choose from the following options.a) Both A and R are true and R is the correct explanation of Ab) Both A and R are true, but R is not a correct explanation of Ac) Both are falsed) A is false, but R is trueCorrect answer is option 'A'. Can you explain this answer? for UPSC 2025 is part of UPSC preparation. The Question and answers have been prepared according to the UPSC exam syllabus. Information about Assertion (A): Coral reefs are generally absent on the Western coasts of continents Reason (R): Coral reefs do not flourish where there are cold currents Choose from the following options.a) Both A and R are true and R is the correct explanation of Ab) Both A and R are true, but R is not a correct explanation of Ac) Both are falsed) A is false, but R is trueCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for UPSC 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Assertion (A): Coral reefs are generally absent on the Western coasts of continents Reason (R): Coral reefs do not flourish where there are cold currents Choose from the following options.a) Both A and R are true and R is the correct explanation of Ab) Both A and R are true, but R is not a correct explanation of Ac) Both are falsed) A is false, but R is trueCorrect answer is option 'A'. Can you explain this answer?.
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