知识贝壳
知识贝壳
所属栏目：英汉双解生物学
Developing from the base upwardsso that the youngest structures are at the apex.An acropetal sequence of development is seenin flower formation in which the calyx formsfirst and the carpels form last. The term mayalso be applied to the movement of substan ......（本文共 456 字 ） [阅读本文] >>