How can you detect that a chemical reaction has occurred? select all that apply.
a precipitate has formed.
a color change has occurred.
a gas has formed.
a phase change has occurred.
a temperature change occurred.

All, except for "a phase change occured". That would be a physical change. Say for example we had an ice cube (solid). and it melts into water. It becomes a liquid. However, it is still water. Although the phase changed, it's composition did not change.

That result from subduction of oceanic plates beneath lighter continental plates. most of the earth's volcanoes are located around the pacific ring of fire because that the location of most of the earth's subduction zones.