Biology

The correct answer is D.Spindle Fibers.

During prophase (the first stage of mitosis), the centrioles move to opposite poles of the cell and begin to form spindle fibers. These fibers are made of microtubules and will eventually help in the separation of sister chromatids during later stages of mitosis.

Here’s a brief explanation of the other options:

A.Chromosomes: Chromosomes are already present in the nucleus, ...