Question

spindle fibers
the purpose of the spindle fibers is to
multiple choice
assist in the condensing of chromatin into chromosomes.
aid in sorting and aligning the chromosomes for their movement to opposite ends of the cell.
assist in the replication of chromosomes.
aid in the growth of a new plasma membrane upon cytokinesis.

Explanation:

Spindle fibers are part of the cell's machinery during cell division (mitosis or meiosis). Their main role is related to chromosome movement.

• Chromatin condensing into chromosomes is mainly due to other processes like histone - related changes, not spindle fibers.
• Chromosome replication occurs during the S - phase of the cell cycle, well before spindle - fiber - significant stages (like metaphase and anaphase).
• The growth of a new plasma membrane during cytokinesis is more about membrane - related components (like vesicles fusing) rather than spindle fibers.
• Spindle fibers (composed of microtubules) attach to chromosomes (via kinetochores) and help in sorting (aligning them at the metaphase plate) and then moving them to opposite poles of the cell during anaphase.

Answer:

aid in sorting and aligning the chromosomes for their movement to opposite ends of the cell.