Key Concept: Frozen vegetables can still spoil because enzymes remain active at freezer temperatures unless deactivated first.
Why it's correct: Blanching briefly boils/steams vegetables specifically to inactivate these spoilage enzymes, preserving color, texture, and nutrients through storage.
Why others fail: Flavor enhancement and microbial reduction are side effects at best, and blanching doesn't increase moisture content — enzyme inactivation is the defined, primary purpose.