If a cell is exposed to a chemical that inhibits the production of spindle fibers as the cell is preparing for mitosis, what would most likely happen?

Cell division will halt/discontinue

Explanation:

During mitosis, the chromosomes align at the cell's equator while spindle fibers from the opposite poles of the cell engage the chromosomes at the kinetochore of the centromere. The spindle fibers then start shortening towards the opposite poles, pulling apart sister chromatids in the process. The chromatids eventually migrates to the poles and the cytoplasm divides, resulting in the formation of two daughter cells.

If spindle fibers formation is chemically inhibited, the dividing cell will not be able to proceed beyond metaphase. There will not be any structure to separate the chromosomes into chromatids and assist the chromatids to migrate to the poles. Mitosis will be stuck and cell division will eventually stop.