8. occurs at ocean ridges, whereas occurs at subduction zones.

a. flux melting; decompression melting

b. decompression melting; flux melting

c. formation of intrusive rocks; formation of extrusive rocks

d. formation of extrusive rocks; formation of intrusive rocks

The correct answer is option b. Decompression melting; flux melting.

Explanation:

The Decompression melting process takes place in mid-ocean ridges.

What happens here is that two plates are separated, and the space between them is filled with hot rock that emerges from below. If this rock rises quickly before it can cool, it melts as the pressure drops as the rock approaches the surface.

Flux melting occurs when a solid rock is hot and receives water or other volatile components. This process is found in the subduction zones, where the rock of the upper mantle is melted by the addition of these materials that come from the descending plate.