Answer:
A persons' parents genes (and maybe Natural Selection)
The answer is a tumor.
Tumors are characterized by cells that have a mutation in their DNA that causes them to reproduce unregulated hence proliferate and do not form true tissues. Inhibitors, called tumor suppressors, act like a ‘brake’ in the cell cycle. Cyclins, on the other hand, are the ‘gas pedal’ for the cycle. The right balance ensures that cell cycle is well regulated. When the DNA is a cell is damaged, the tumor suppressors are rectruited to stop any further progress of the cell cycle and the cell undergoes apoptosis.
A virus is a small, infectious agent that is made up of a core of genetic material surrounded by a shell of protein. The genetic material (which is responsible for carrying forward hereditary traits from parent cells to offspring) may be either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA). Viruses are at the borderline between living and nonliving matter. When they infect a host cell, they are able to carry on many life functions, such as metabolism and reproduction. But outside a host cell, they are as inactive as a grain of sand.<span>
Read more: <span>http://www.scienceclarified.com/Ti-Vi/Virus.html#ixzz4e9PRRTSF</span></span>
Species because i sreach is on google
