Final answer:
The primary mechanism of most antineoplastic agents is to inhibit rapidly growing cells.
Step-by-step explanation:
The primary mechanism of most antineoplastic agents is to inhibit rapidly growing cells. Chemotherapy drugs interfere with cell division in various ways, such as by stopping the duplication of DNA or the separation of newly formed chromosomes. By targeting rapidly growing cells, these drugs aim to slow down or halt the growth of cancer cells. However, it's important to note that these drugs are not specific to cancer cells and can also affect normal cells that naturally have a rapid turnover, leading to common side effects associated with cancer chemotherapy.