How do you decide when to use "essere" or "avere" as an auxiliary verb in the passato prossimo? (past participle)

Most verbs in the past participle of Italian use, "avere," as the auxiliary verb. However, verbs of movement (correre, camminare, ecc.) use "essere." Reflexive verbs, "lavarsi," also use "essere."

What is a run-on sentence? How do you correct such an error?

A run-on sentence is a sentence where there are two independent clauses joined with incorrect punctuation. An error like this can be corrected by splitting the two clauses into two independent sentences, or using correct punctuation, such as a semi-colon.

What is the difference between Cluster A and Cluster B Personality Disorders?

Cluster A personality disorders are defined with odd and eccentric behaviors. Some personality disorders in the Cluster A group are Paranoid Personality Disorder, Schizoid Personality Disorder, and Schizotypal Personality Disorder. Cluster B personality disorders are defined with dramatic and erratic behaviors. Some personality disorders in the Cluster B group are Antisocial Personality Disorder, Borderline Personality Disorder, Histrionic Personality Disorder, and Narcissistic Personality Disorder.