Which plant-cell organelle supports and maintains the cell's shape and protects the cell from damage?

The plant-cell organelle which supports and maintains the cell's shape and protecs the cell from damage would be the cell-wall.

The cell wall is there to maintain stability and enable any plant (cell) to maintain its shape. Without it, it's a good question what would happen.

Cell wall

The cell wall of the plant cell protects it, and maintains the framework and shape. This cell wall is an important part of the cell because it draws the internal and external elements within and without the cell. This structure serves as the rough edge and why plants have this thick structure outside when you try to feel it.