CompTIA A+ 220-1001/1002 Practice Test

Answer: A - Worms self-replicate in the system, while Trojans performs undisclosed malicious activities on the host computer.

Key Takeaway:
A computer worm is a self-replicating computer program that generally cause harm to a network, at least by consuming bandwidth, but are not necessarily harmful. Viruses almost always corrupt or devour files on a targeted computer. A Trojan is a malware that appears to perform a desirable function but in fact facilitates unauthorized access to the user's computer system.