Final answer:
A virus is a type of malware that attaches to a host file and can replicate itself using the host cell's machinery.
Step-by-step explanation:
A virus is a type of malware that is attached to a host file and has the ability to replicate, or copy, itself.
Viruses are not cells; they are a strand of genetic material within a protective protein coat called a capsid. They infect a wide variety of organisms, including both eukaryotes and prokaryotes. Once inside the cell, they use the cell's ATP, ribosomes, enzymes, and other cellular parts to replicate.
After infecting a host cell, a virus uses the cell's machinery and metabolism to produce new copies of itself.