A:充分不必要条件
B:必要不充分条件
C:充要条件
D:既不充分又不必要条件
—The difficult maths problem has been solved by Tom at last.
— Indeed; and the ___ way Tom worked out the problem impressed the teacher deeply.
顶端优势的现象表示植物生长素在植物体内的运输方式是( )