Establish a correspondence between the types of anti-virus programs and how they work.

Scanners – launched at the user’s request. Provides search and detection of viruses.
Auditors – creates a database with checksums and other information, allowing you to notice the change in any file.
Monitors (watchmen) are a resident program. Provides constant protection.
Immunizers (vaccines) – protects the system from being damaged by viruses of known types.
Polyphages (doctors) – finds files infected with viruses and “cures” them ie removes the body of the virus program from the file.