Question

if two distinct lines intersect, then their intersection is exactly one point. postulate #3: if two distinct planes intersect, then their intersection is a line. postulate #4: if you have three distinct noncollinear points, then there is exactly one plane that contains them. what characteristic of planes ensures that the intersection of two distinct planes is a line? the planes are the same plane the planes are flat and extend infinitely in all directions the planes are curved the planes can be horizontal, vertical, or diagonal.

Explanation:

Planes are flat and infinite. When two distinct ones intersect, their infinite - extending nature results in a line of intersection.

Answer:

The planes are flat and extend infinitely in all directions