Answer: b) cancer
Explanation:
A pathogen is an biological agent which is capable of invading the body of living beings and harm them by causing infection. Cancer and pollen cannot be considered as pathogens.
Cancer is a condition in which the cells of the body divide uncontrollably in an abnormal fashion. Due to this tumor of abnormal cells develop and these cells makes the immune system of the body weak. These infectious cells make the immune system weak and prove to be fatal.
