The shape has 4 right angles. This shape is a square (turned 45°). You know this because each vertice intersects on the 3rd unit on the edge of the grid (this might be confusing but it's the only way I can explain). A square has 4 right angles.
It has 4 straight sides. This shape is a polygon, and it has 4 straight sides (polygons must have 3 or more straight sides).
It has 2 pairs of parallel lines. A square always has 2 pairs of parallel lines. The one on the top and the one on the bottom, and the one on the left and the one of the right. If you tilted the square in this picture, you'd see the parallel lines.
4 sides are the same length. On a square, every side is the same length.