Answer:
1.Vertical Angles theorem
2.Angle BED
Explanation:
We are given that a figure in which segment AB is parallel to segment CD
We have to fill the correct answer in the blank space

Given
Angle AEB is congruent to angle CED
By Vertical Angles theorem
Vertical angles theorem : When two lines intersect to each other then opposite angles are congruent .
Angle AEC is congruent to angle BED
By Vertical Angles theorem