User blog comment:BobTheDoctor27/February 2013 Update/@comment-5918010-20130312003428/@comment-5918010-20130313195118

With the ratio of organic to mechanical, members of the Matoran species have tissue and armor, although the armor likely stops most bleeding (since there would be a blood-like substance to help maintain their bodies, like real blood does) Also, other known organs present in Bionicle: Brain, Lungs(since all but Makuta have to breathe), and reasonably muscle of some sort, while they do have mechanical eyes, and do have a need to eat for energy.