题目

Flow like the river of changeLittle stream ran down from a high mountain through many villages and forests. Then it reached a desert. “I went through so many difficulties. I should have no problem crossing the desert,” she thought. As she started, she found herself slowly disappearing into the sand. After many tries, she still failed. “Maybe I can’t reach the ocean,” she said sadly to herself. At this time, a deep voice said, “If a breeze(微风) can cross the desert, so can a river.” It was the voice of the desert. But the little stream answered, ‘‘That’s because a breeze 生物兴趣小组的同学对某品种番茄的花进行人工去雄后，用不同浓度的生长素类似物2，4—D涂抹子房，得到的无籽番茄果实平均重量见下表。据表得出的正确结论是（    ）2，4—D浓度（mg／L）05101520253035无子番茄平均重量（g/个）013.526.246.553.653.743.030.2 2，4—D浓度( mg／L)05101520253035无籽番茄平均重量(g／个)013.526.246.553.653.743.030.2A．2，4—D浓度为35 mg／L，对果实的发育起促进作用B．2，4—D与生长素的作用效果相同C．2，4—D可以促进扦插枝条生根D．2，4—D诱导无籽番茄的最适浓度范围为20—25 mg／L