Clades can be very large, like the clade that includes all animals, called metazoa.

进化枝可以非常大，比如包含所有动物的进化枝，这称为后生动物。

Although they seem to be of little relevance, they're good candidates for studying the evolution of metazoans because they represent the most ancestral state of the group.

虽然它看起没什么关系，但它究后生动物进化的好候选人，因为它代表了这个群体最古老的状态。

And what they were trying to figure out is where metazoans fit and who is related to whom.

而他试图弄清楚的，多细胞动物在进化树中的位置，以及哪些生物之间有亲缘关系。