What defines a carcinogen?

A carcinogen is specifically defined as a substance that has the potential to produce malignant tumors, which are types of cancer. This definition is grounded in extensive scientific research that has identified certain chemicals and agents as capable of causing cellular changes that lead to tumor formation and cancer development in humans and animals.

Other substances listed are not related to cancer. For instance, something that enhances plant growth is beneficial in agriculture but does not pose a risk of cancer. Similarly, a chemical that promotes pest resistance is focused on managing pests and not on health risks related to cancer. Lastly, a benign agent used in pesticide formulations implies safety and non-harmfulness, thus not associated with the properties of a carcinogen. Therefore, the correct identification of a carcinogen lies in its ability to lead to malignant tumors, marking it distinct from others that serve beneficial roles in agriculture or pest management.