Question

the flow chart shown includes some parts of the excretory system. which terms should go in the areas that are marked with a w and a z to best complete this chart? w: tissues; z: organism w: organ; z: organism w: organ system; z: organism w: tissue; z: organ system

Explanation:

生物的结构层次为：组织→器官→器官系统→生物体。肾脏（kidney）属于器官，构成它的是组织（tissue，此处指代肾脏的组织，用单数形式）；排泄系统（excretory system）是器官系统，更高一级的结构是生物体（organism）。

Answer:

W: tissue; Z: organism