What role does the capsid play in relation to a virus?

The capsid serves as the protective outer shell of a virus, composed of protein subunits called capsomers. Its primary role is to encase and shield the virus's genetic material, whether it be DNA or RNA, from external factors that may degrade it, such as environmental elements or the immune responses of a host organism. In addition to offering structural support, the capsid is crucial for maintaining the integrity of the viral genome during transmission between host cells.

Furthermore, the capsid can also play a role in the initial stages of a viral infection by facilitating the attachment of the virus to a host cell. However, its essential functions revolve around the protection and structural support it provides. Thus, the correct answer emphasizes the importance of the capsid in safeguarding a virus's genetic material while contributing to its overall structural integrity.