Computer Science Homework Help

I’m working on a computer science discussion question and need an explanation and answer to help me learn.

Trojan Horse

A Trojan horse is an application that appears to have a benign purpose but actually performs some malicious function. How do Trojans get onto our systems? What is the purpose of a Trojan and why do people create them? What is the most effective way to remove a Trojan? Recommend at least one tool to help prevent Trojans from attacking your system.