Final answer:
A worm is a self-replicating program that spreads through computers and networks. It does not need a host file and can exploit vulnerabilities in systems.
Step-by-step explanation:
A worm is a fully-contained program that self-replicates and spreads through computers and networks. Unlike a virus, a worm does not need a host file to spread. It can independently spread across systems, often exploiting vulnerabilities in operating systems or network protocols.
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