what are viruses

Viruses are microscopic infectious agents that contain genetic material, either DNA or RNA, inside a protein coat called a capsid. They are not considered living organisms because they cannot independently read and act upon the information contained within their nucleic acids. Instead, they must invade a host cell and use its components to make copies of themselves. Viruses can infect humans, animals, plants, bacteria, and fungi, and each one infects only specific types of hosts. Some common diseases caused by viruses include the flu, the common cold, COVID-19, and HIV. Viruses can be spread in different ways, such as through droplets and particles that are breathed out by someone who has the infection, by touching surfaces or objects that have the virus on them and then touching your mouth, nose, or eyes, or through contaminated food or water.