Answer:
1. Two planes intersect to ALWAYS form a line. If two planes intersect, they intersect in a line. The two planes that do not intersect, they form parallel lines.
2. The true statement is :
All quadrilaterals are polygons with four sides. A quadrilateral is a geometrical shape that has four sides and four angles. These are also called polygons. There are many types of quadrilaterals like - the parallelogram, the rectangle, the square, rhombus etc.