Final answer:
When a line intersects two parallel lines, it forms four 90 degree angles, two at each intersection point.
Step-by-step explanation:
The question pertains to the number of 90 degree angles that are formed at the intersections of line EF and two parallel lines AB and CD. When line EF intersects parallel lines AB and CD, it forms four right angles, two at each intersection point. This is based on the geometric property that states when a straight line intersects two parallel lines, the angles formed are either congruent or supplementary. Therefore, if one angle is 90 degrees, the opposite angle must also be 90 degrees, leading to four 90 degree angles in total.