virus is a submicroscopic infectious agent that only inside the living cells of an organism. infect all life forms, from animals and plants to including bacteria and archaea. Viruses found in almost every ecosystem on Earth and are most numerous type of biological entity. I is not correct: Viruses are abundant and in ocean waters. Marine viruses, particularly (viruses that infect bacteria), are the numerous biological entities in the ocean. They a crucial role in regulating microbial populations nutrient cycles. Studies have shown that viruses can in seawater for extended periods, depending on conditions. II is not correct: This statement is inaccurate. or phages, are viruses that specifically and replicate within bacterial cells. They are in environments where bacteria are present, soil, water, and the human body. Phages play significant role in controlling bacterial populations and been explored as alternatives to antibiotics in therapy. III is not correct: Viruses can and often do the transcriptional activity of their host cells. Upon many viruses manipulate the host's gene machinery to favor viral replication and host defenses. For instance, certain viral can interact with host transcription factors, to changes in gene expression that facilitate propagation