Echinoderms lack a centralized nervous system.
Another group of echinoderms are the echinoids.
Echinoids lack a centralized nervous system.
What do echinoids lack?
Options:
1) characteristics
2) centralized nervous system
3) permineralization
4) the body's largest organ
5) biological diversity
6) that material's properties
7) aerobic capacity
8) organic matter