ID folks frequently mention how complex living systems are, but many non-scientists really have no idea what they're talking about. One example of complexity is the biochemical pathways that are found in every cell of a higher animal's body. To get an idea of just what a scientist means by the word "complexity" check this out. As you look at it, bear in mind that this is what Darwinian evolutionists believe was produced by the action of blind, unguided, random processes, and it's what they don't want students to be told may be the product of an intelligent bio-engineer.
Click anywhere on the chart to magnify that section of it.
Thanks to Bill Dembski for the tip.