What are considered carcinogens?

Carcinogens are defined as substances that can lead to cancer in living organisms, either by causing changes in DNA or promoting the growth of cancer cells. The correct choice highlights cancer-causing agents, which include various chemicals, biological agents, and even some physical agents like radiation. These substances have been extensively studied and documented for their ability to induce cancerous changes in cells, which makes understanding their presence and risks essential in the field of public health and safety.

The other options do not fit the definition of carcinogens. Ozone-depleting substances are significant environmental pollutants but are not directly classified as carcinogens. Non-toxic chemicals refer to substances that do not pose a significant risk to human health, and by definition, they wouldn’t be categorized as carcinogenic. Recyclable materials, while important for sustainability, do not inherently have any carcinogenic properties unless specifically known to contain such substances. Thus, the selection of cancer-causing agents as the correct answer underscores the critical aspects of identifying and mitigating exposure to these harmful substances in both environmental and occupational contexts.