I often read of incidents of misunderstanding or conflict. I'm left1.Why do these people create mistrust and problems, especially with those from other2?

    I was growing up in Kuala Lumpur in the early 1960s,3children from different races and religions played and studied4in harmony. At that time my family lived a stone's5from Ismail's. And no one was bothered that Ismail was a Malay Muslim and I was an Indian Hindu-we just6our differences. Perhaps, our elders had not filled our heads with unnecessary advice, well7or otherwise.

    We were nine when we became friends. During the school holidays, we'd8the countryside on our bicycles, hoping to9the unexpected. At times Ismail would accompany my family as we made a rare shopping trip to town. We would be glad of his10.

    When I was twelve, my family moved to Johor. Ismail's family later returned to their village, and I11touch with him.

    One spring afternoon in 1983, I stopped a taxi in Kuala Lumpur. I12my destination. The driver acknowledged my13but did not move off. Instead, he looked14at me. “Raddar?”he said, using my childhood nickname(绰号). I was astonished at being so15addressed(称呼). Unexpectedly! It was Ismail! Even after two16we still recognized each other. Grasping his shoulder, I felt a true affection, something17to describe.

    If we can allow our children to be18without prejudice, they'll build friendships with people, regardless of race or religion, who will be19their side through thick and thin. On such friendships are societies build and20we can truly be, as William Shakespeare once wrote, “we happy few, we band of brothers”.

下列哪项是腔肠动物和扁形动物的共同特征（　　）