Step-by-step explanation:
The three statements that are true are:
At the Cascadia Subduction Zone, the Juan de Fuca plate is subducting under the North American plate. This is an example of a convergent plate boundary.
Extensional stress is present at divergent plate boundaries, such as mid-ocean ridges.
The San Andreas Fault is a transform boundary, where the Pacific plate is moving northwest relative to the North American Plate.
The following statements are false:
The Earth's tectonic plates are not currently moving. This statement is false because tectonic plates are constantly moving due to the convective motion of the mantle.
When two oceanic plates collide, subduction does not result. This statement is false because when two oceanic plates collide, the denser plate will subduct beneath the other plate, leading to the formation of subduction zones.