Answer: d. carcinogens
Explanation:
A carcinogen is any substance or radiation which is likely to cause damage to the genome of the organism and disturbing the cellular metabolic processes. These causes mutation in the genome which is responsible for the proliferation and uncontrolled cell division of abnormal cells a condition called as cancer. Carcinogens are of the following types:
Biological (bacteria)
Chemical ( nicotine and asbestos)
Physical (UV radiations)
On the basis of the above explanation, the cancer causing agents are called carcinogens.
