Which of the following are based on malicious code? Each correct answer represents a complete solution. Choose two.

A Trojan horse is malicious code that disguises itself as a legitimate or benign program to deceive users into executing it, causing harm such as opening backdoors or stealing data - it is definitively malicious code.

A worm is self-replicating malicious code that propagates across networks without requiring user interaction, consuming resources and potentially delivering destructive payloads - it is a core category of malware.

Biometrics is an authentication technology that uses unique physical or behavioral traits to verify identity - it has no relationship to malicious code or malware categories.

Denial-of-Service is a network attack technique that overwhelms a target with traffic or requests - while DoS tools may sometimes be malware-delivered, DoS itself is an attack method, not a malicious code category.