Question

Assertion (A): The spindle fibers play a crucial role in chromosome movement during cell division.

Reason (R): They attach to the centromeres and help separate sister chromatids.

Options

• Both A and R are true and R is the correct explanation of A.

• Both A and R are true but R is not the correct explanation of A.

• A is true but R is false.

• A is false but R is true.

Answer 1

Both A and R are true and R is the correct explanation of A.

Explanation:

The assertion is true because spindle fibres (made of microtubules) provide the mechanical force necessary to dynamically pull and guide chromosomes during cell division. The reason is also true and serves as the correct explanation because it details the exact mechanism behind this movement: by attaching securely to the centromeres (via kinetochores), the contracting spindle fibres can successfully split the chromosomes and drag the separated sister chromatids to opposite poles.