You are sound asleep. your dog decides to get up and walk around the house and in the process steps on a lose floor board and causes it to make a cracking sound. you wake up! what structure was responsible for waking you up from sleep?

Reticular activating system.

Explanation:

Reticular activating system may be defined as the system containing different nerves stimulation and located in the mesopons. This system interacts with thalamocortical systems and  basal forebrain.

The reticular activating system is involved in the resting sleep, dreaming and asleep. The sound of a particular object or living organism play important role in the reticular activating system. The individuals asleep and waking and its regulation is controlled by this system of nervous system.

Thus, the correct answer is reticular activating system.