The correct order for the missing words in the passage is:
"Weathering and erosion are the processes where rock is broken down to create sediment. Sediment then goes through the processes of compaction and cementation to form sedimentary rock. This is exposed to heat and pressure, producing metamorphic rock, which then can melt into magma and cool into igneous rock."
So, the correct choice is:
weathering and erosion; compaction and cementation; heat and pressure; melt; cool