Basis of liability for offenses

1. A person commits an offense only if the person engages in conduct, including an act, an omission, or possession, in violation of a statute which provides that the conduct is an offense. 2. A person who omits to perform an act does not commit an offense unless the person has a legal duty to perform the act, nor shall such an omission be an offense if the act is performed on the person's behalf by a person legally authorized to perform it.