一问：

zyh79

Unlik other arachinids,which have their nerve cells evenly distributed along thier (body, the scorpions has a cluster of nerve cells in its head, as a mammal does.)
为什么是body，而不是bodies ?

lucylu

body这个词一般当“品质”讲时，才是不可数名词，不用复数。当身体或躯体讲时，可单可复。当指一个一个的时，用复数；当指单个的集合体时，用单数。在此句中，body概述arachinids的集合体，所以可用单数。