Which of the following would most likely cause geographic isolation? volcanic eruption < i think it's this one a large tree falling widening of a lake a forest fire,

A volcanic eruption would likely cause the most geographic isolation, as the extreme heat would make it impossible to even get near anyone living nearby. If a lava flow were to create a wall between two areas, it would be nearly impossible to cross it until well after the lava had cooled from the thousands of degrees it is when it exits the earth.

The answer would be abrasion.

Amillion dollars