What's the Central Nervous System?

From fish onwards, they have a centralized system. And this is essentially the central nervous system which you're about to explain. The higher order invertebrates would be like spiders and insects. They have more of a diffuse nervous system network. But then as you move up to a more complicated but let's us jump into the vertebrates. We've got vertebral column, ora, vertebleargess column, protects theacbone, deactiv backbone. Ye, protects the spinal cord. Yes. So they're also in the filum called the cordata. Wic comes from, noto cord. It basically has these projections that come off the brain and the spinal cord -