The correct option is D All of the above
Characters of living nature of viruses are: Viruses have genetic material (DNA or RNA). They can mutate. They can grow, once inside the host cell. They can be transmitted from one host to another. They are capable of multiplication within a host. They react to heat, radiation and chemicals. They show irritability. They bring about enzymatic changes in vitro. They are able to infect and cause the disease to living beings. The DNA and proteins of viruses are similar in composition and structure to those of higher organisms. Thus, the correct answer is option D.