What is defined as the property of an agent being toxic to cells?

Cytotoxicity is the property of an agent that is harmful or toxic to cells. This term is commonly used in the fields of medicine and toxicology to describe substances that can kill or damage cells. Cytotoxic agents can be natural or synthetic and are often studied for their effects in various contexts, including cancer treatment, where certain drugs target and destroy rapidly dividing cancer cells.

In contrast, toxicology is the broader study of poisons and their effects, but it does not specifically refer to the damage caused to cells. Cancerogens refer specifically to substances that can lead to cancer but do not define cell toxicity overall. Pathogenicity refers to the ability of an organism, such as bacteria or viruses, to cause disease, which may involve various mechanisms including but not limited to direct cell toxicity.

Therefore, cytotoxicity specifically captures the essence of being toxic to cells, making it the correct answer.