A virus is a type of malware that can infect a computer or other device and replicate itself, often causing damage or disruption to the device's normal operation. Some viruses are designed to specifically target certain operating systems, while others are more general and can infect a variety of different types of devices and systems.
It is possible for a virus to specifically target a certain operating system, in which case it would depend on that operating system in order to function. However, many viruses are designed to be more general and can infect multiple types of operating systems.
The best way to protect against viruses is to use antivirus software, keep the operating system and other software up to date with the latest security patches, and practice safe browsing and email habits.