Final answer:
Vincristine is the drug used to promote polyploidy by disrupting normal chromosome segregation during cell division.
Step-by-step explanation:
The drug that is often used to promote polyploidy because it binds to the microtubule spindle apparatus and disrupts normal chromosome segregation during cell division is vincristine.
Vincristine is a plant alkaloid that prevents cell division, or mitosis, by binding to tubulin, a protein that helps in the formation of microtubular fibers called spindles. By binding to tubulin, vincristine inhibits the formation of spindles and disrupts cell division.
This interruption in chromosome segregation can lead to the formation of cells with an abnormal number of chromosomes, a condition known as polyploidy.