Please choose the statement that best describes the role of viral surface proteins or spikes.
1. Viral spikes allow viruses to bind to each other.
2. Viral spikes provide means of attachment to host cell surface.
3. Viral spikes provide means for viruses to exchange nucleic acid.
4. Viral spikes enable replication of the viral nucleic acid.
5. Viral spikes inject viral nucleic acid into host cell.