A virus is a small parasite that cannot reproduce by itself. Viruses are made of genetic material and protein coat. They do not have cellular machinery required for viral multiplication. Once it infects a susceptible cell, the virus can direct the host cell machinery to produce the viral genome and viral proteins to make new capsids. Next, the viral particles are assembled into new viruses. These new viruses burst out of the host cell by lysis which kills the host cell. So, the correct answer is 'Lack of cellular machinery to use its genetic material'.