Viral particles are tiny (20–300 nm) symmetrical structures built from repeating elements. Each virus is a particle of a nucleic acid (DNA or RNA) enclosed in a protein coat called a capsid. Viruses are not capable of independent life: they can display the properties of a living creature only by penetrating the cell and using its structures and energy for their needs. Thus, viruses are intracellular parasites. Some viruses, such as the influenza or herpes virus, leaving the host cell, capture a portion of the cell membrane and form an additional membrane from it on top of their capsid.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.