Question

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Heterosporous species of pteridophytes are dioecious. Reason (R) : The gametophyte develops within the spore wall in heterosporous species. In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Hetero means different. Different types of spores automatically give rise to two different homes for gametes (Dioecious), while their development remains cozy inside the original spore walls (Endosporic).

Answer 1

The Correct Option is B

Step 1: Concept
Heterospory is a condition in plant life cycles where two distinct morphological types of spores are produced: small microspores and larger megaspores.

Step 2: Meaning
Microspores germinate into male gametophytes, while megaspores germinate into separate female gametophytes. Because these male and female sex organs reside on separate gametophytic plants, the species are functionally dioecious.

Step 3: Analysis
Assertion (A) is correct because heterosporous pteridophytes produce distinct male and female gametophytes, making them dioecious. Reason (R) is also correct because heterosporous species exhibit endosporic development, meaning the gametophytes grow and develop internal to the protective boundaries of the spore wall. However, endosporic growth is a structural protection mechanism and is not the direct biological reason why the species are split into separate sexes.

Step 4: Conclusion
Both statements are independently factually correct, but Reason (R) does not explain the cause behind Assertion (A). This corresponds to option (2) from the image, matching structural option (B). Final Answer: (B)