Final answer:
Slurred speech is a sign of impaired motor coordination.
Step-by-step explanation:
The behavior that is a sign of impaired motor coordination in a guest is slurred speech. Slurred speech is characterized by difficulties in pronouncing words clearly and accurately, and it is often a result of impaired muscle control in the mouth and tongue. This impairment can be caused by various factors such as alcohol or drug intoxication, neurological disorders, or certain medical conditions.