Virus does not possess nuclei, organelles, or cytoplasm that can regulate the process of metabolism. As a result of which they do not survive in the environment.
A virus consists of a strand of DNA or RNA covered by a protein coat.
This presence of nucleic acid (DNA or RNA) suggests that viruses are alive.
In addition, they can also respond to their environment (inside the host cell) in a limited manner means, while living inside the host they respond to the host cell where they live.