如图表示植物体的不同结构层次，其中属于组织的是（　　）

在研究水滴下落规律的实验中，答开水龙头让水一滴一滴下落，并用频闪照相机每隔0.1s拍摄了同一水滴下落时的不同位置，如图所示，有图可知，水滴下落0.3s内的平均速度是（　　）

赵立军同学从小就很羡慕飞行员，立志将来长大了自己也要当一名飞行员。可是在高考体检时，因视力不合格，不能报考航空院校，这使立军同学情绪非常低落。造成他产生挫折感的原因是   （   ）  

    Hello! Look here! There's 1 apple tree behind Dick's house. Dick is near the tree. There are some apples 2 the tree. Dick is looking 3the apples. They are big and red. Dick is hungry. He wants to 4 an apple. Dick isn't tall. He is short. He can't reach(够到) the apples. He puts a 5 under the tree. Can he reach the apples on the box now?6, he can't. He is too7. Here comes Paul. He is Dick's brother. “Hello, Dick,8 do you want to do?”

     “Please help9, Paul. I can't 10 the apples.”

     “Here you are, Dick. One is for you, and one is for me!”

     “Thank you, Paul.”