The first time a pathogen hits, our bodies do not know how to handle it properly. This means that our bodies take more time to handle it the first time around. The second time around, however, our bodies have altered so that they can handle the pathogen more efficiently. Hope this helps!
The answer is D. The presence of oncogenes
Oncogenes is a gene that has potential to cause Cancer. Once it appear on tumor cells, Oncogenes often mutated at a very high level. When the cells critical function altered, they usually undergo a rapid cell death. But once oncogenes activated, those malfunction cells will not undergo rapid cell death, filling our body with malfunctioning cells
