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Assertion (A): Cyanobacteria are capable of photosynthesis and nitrogen fixation due to the presence of chlorophyll and specialized cells called heterocysts.

Reason (R): Cyanobacteria can only perform photosynthesis in aquatic environments due to the absence of light in terrestrial environments.
  • 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 the correct explanation of (A).
  • c)
    (A) is true, but (R) is false.
  • d)
    (A) is false, but (R) is true.
Correct answer is option 'C'. Can you explain this answer?
Most Upvoted Answer
Assertion (A): Cyanobacteria are capable of photosynthesis and nitroge...
Assertion (A) is correct because cyanobacteria can perform photosynthesis using chlorophyll a and can fix nitrogen in specialized cells called heterocysts. These abilities help them thrive in various environments, including freshwater and marine ecosystems.

However, Reason (R) is incorrect because cyanobacteria can perform photosynthesis in both aquatic and terrestrial environments, as long as there is sufficient light. The assertion is correct, but the reasoning given is false, so the correct answer is Option C.
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Community Answer
Assertion (A): Cyanobacteria are capable of photosynthesis and nitroge...
Assertion (A) Explained
Cyanobacteria are indeed capable of photosynthesis and nitrogen fixation. They possess chlorophyll, which allows them to capture light energy and convert it into chemical energy through photosynthesis. Additionally, they have specialized cells known as heterocysts that facilitate nitrogen fixation, converting atmospheric nitrogen into a usable form for the organism.
Reason (R) Explained
The statement that cyanobacteria can only perform photosynthesis in aquatic environments is not accurate. While they thrive in aquatic settings where light is abundant, cyanobacteria can also be found in various terrestrial environments, such as soil and on rocks, where they can still engage in photosynthesis, especially when moisture is available.
Conclusion
Therefore, the correct interpretation is:
  • (A) is true: Cyanobacteria can photosynthesize and fix nitrogen.
  • (R) is false: Cyanobacteria are not limited to aquatic environments for photosynthesis.

The correct answer is option 'C', indicating that while the assertion is true, the reasoning provided is incorrect. Cyanobacteria's ability to perform photosynthesis is not restricted to aquatic environments, making (R) false.
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