Question

why is the unsaturated zone not filled with water?
it is below the water table and water stays above it.
it is clay and water pools above it.
it is granite and water flows around it.
it is permeable and water flows through it.

Explanation:

The unsaturated zone is above the water table. It consists of permeable materials (like soil, sand, gravel). Water can infiltrate and flow through these permeable materials (due to gravity and the nature of permeability), so it's not completely filled with water. Clay has low permeability (water would pool above it less likely to be in the unsaturated zone context here as described in the question). Granite is impermeable but that's not the typical characteristic of the unsaturated zone. And the unsaturated zone is above the water table not below.

Answer:

It is permeable and water flows through it.