Viruses - Gabriel Ramirez - Bog

Where did viruses come from? What are viruses? Are virus's life forms?Are there any bacteria that attack other cells by eating them from the inside out? Are bacteria and viruses the same thing? What are the blood cells? How does the cell know when to divide? What gives a signal? What is the signal? And how does it cause the DNA to condense? What's the difference between positive blood types and harmful blood types?