Assertion: Eukaryotic cells show extensive compartmentalisation of cytoplasm.

Reason: The presence of membrane - bound organelles is an important character in eukaryotes:

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

The assertion and reason provided relate to the characteristics of eukaryotic cells. Let's break them down:

Assertion Analysis

The assertion states that eukaryotic cells exhibit extensive compartmentalization of the cytoplasm. This is true, as eukaryotic cells contain various membrane-bound organelles, such as the nucleus, mitochondria, and endoplasmic reticulum, which compartmentalize different cellular functions.

Reason Evaluation

The reason given is that the presence of membrane-bound organelles is a significant feature of eukaryotes. This statement is also true, as these organelles are indeed a defining characteristic of eukaryotic cells.

Relationship Between Assertion and Reason

However, while both statements are true, the reason does not directly explain the assertion. The assertion about compartmentalization is more about the functional organization of the cell, while the reason focuses on the existence of organelles.

Conclusion

Based on this analysis, the correct answer is:

• B: Both (A) and (R) are true but reason is not the correct explanation of (A).