Final answer:
Animal viruses can enter host cells through endocytosis or membrane fusion, while plant viruses enter through damaged tissues in plants or are transmitted by vectors or pollen.
Step-by-step explanation:
Animal viruses can enter host cells through endocytosis or membrane fusion. Non-enveloped animal viruses can be taken inside the cell through receptor-mediated endocytosis, where the viral capsid binds to a receptor on the host cell and is engulfed in a vesicle. Another method used by non-enveloped viruses is for capsid proteins to create channels in the host cell membrane and inject the viral genome through these channels. On the other hand, plant viruses do not use receptor-mediated endocytosis as they infect plant cells, which have a cell wall. Instead, plant viruses enter host cells through damaged tissues caused by weather, insects, or human activities like farming or landscaping. They can also be transmitted through vectors like insects and nematodes, or through pollen.