It would be nice if someone explained the specific biological reason for why they are different. Like, because they target different types of cells, or reproduc

It would be nice if someone explained the specific biological reason for why they are different. Like, because they target different types of cells, or reproduce in different ways. The lay explanation of a virus is that it invades your cells and hijacks their machinery to make more of itself. That makes them all sound the same. For bacteria we at least can understand that they have different types of metabolism, come in different shapes, produce different defensive compounds, etc.