"This is an easy one! The main difference between a virus and a worm, both of which are considered kinds of malware, is that viruses have to be triggered by the activation of their host. In other words, someone needs to execute it or enable a macro in order for the virus to begin inserting its code into other programs on the device. On the other hand, worms are stand-alone malicious programs that don't require a host program or file. Instead, they self-replicate and propagate independently once they breach a system without the need for any human activation. A worm is usually considered more dangerous than a virus because it can spread faster, sometimes at an exponential rate."