Final Answer:
Mary presses her foot on the gas pedal to make the car go faster. Mary's ankle is undergoing dorsiflexion.
Step-by-step explanation:
Dorsiflexion: Mary is pressing her foot on the gas pedal to accelerate, causing her ankle joint to decrease the angle between her foot and the front of her leg. This motion is dorsiflexion.
Gas Pedal Action: Pressing the gas pedal involves extending the ankle joint, specifically dorsiflexion, as the top of the foot moves towards the shin.
Anatomy: Dorsiflexion and plantarflexion are movements primarily associated with the ankle joint. Dorsiflexion involves bringing the top of the foot towards the shin, which aligns with Mary's action on the gas pedal.