Two adjacent, supplementary angles form a(n)

right angle
obtuse angle
line

Answer;

-Line

Two adjacent, supplementary angles form a straight line

Explanation;Supplementary angles are those angles whose sum add up to 180 degrees. Thus, two angles are said to be supplementary if their sum adds up to 180 degrees.Similarly, angles on a straight line add up to 180 degrees, which means they are supplementary angles.Thus, two adjacent supplementary angles add up to 180 and it means they are on a straight line.