Phase Changes in Matter Steps:

• Examine the diagram: X transitions gas to liquid, Z transitions liquid to solid, W transitions liquid to gas, Y transitions solid to liquid.
• Match X (gas to liquid) to condensation, as it reverses vaporization.
• Match Z (liquid to solid) to freezing, the opposite of melting.
• Match W (liquid to gas) to boiling, a form of vaporization.
• Match Y (solid to liquid) to melting, increasing molecular energy to break solid bonds.

Why D is correct:

• D aligns with definitions: boiling (liquid → gas), condensation (gas → liquid), melting (solid → liquid), freezing (liquid → solid).

Why the others are wrong:

• A: Misassigns boiling to X (gas → liquid) and melting to Z (liquid → solid).
• B: Places condensation as W (liquid → gas) and boiling as X (gas → liquid).
• C: Assigns melting to Z (liquid → solid) instead of freezing.

Final answer: D