The paragraph is followed by an incomplete phrase or sentence which summarizes the main idea of the paragraph. Choose the missing words of the phrase or sentence.

Some people feel very nervous when they fly in airplanes. No matter how hard they try, they cannot lower their anxiety. Many notice their anxiety but only a few are conscious of the way they express their tension. Some try to hide their nervousness; some become aggressive, attacking people by making them the butt of cruel jokes.
Different （）to tension when flying.