Final answer:
The force that causes the wind to flow across the isobars is the Coriolis force.
Step-by-step explanation:
The force responsible for causing the wind to flow across the isobars is the Coriolis force. The Coriolis force is a result of Earth's rotation and causes moving objects, like air, to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This deflection leads to the characteristic clockwise rotation of wind around high-pressure zones and counterclockwise rotation around low-pressure zones.