Biological, yep.

And yeah, see, you'd think that from a storytelling perspective.

Keep in mind (Bioniclestory.com spoiler alert) that the Great Beings originally intended them to be robots. Self awareness was a glitch in the system.

Any flatness in characterization can thus be handwaved, like the master of his technique that old Farshtey is.

EDIT: Don't click the link. It goes to bionicle 2015 now.