What's one similarity between echinoderms and humans?
Echinoderms and humans are both multicellular (made of more than one cell). They are also both a part of the Kingdom Animalia.
The phylum Echinodermata contain sea urchins, starfish, and allies. Sea urchins are considered to be invertebrates. They contain 5-rayed symmetry that is mostly radial but sometimes bilateral. They contain a true coelom, a poorly defined open circulatory system, and lack excretory organs. The feed on fine particles in the water, detritus, or other animals. Their tentacles or tube feed in their feeding.
Mammals are warm-blooded vertebrates (chordata) with a closed ciruclatory system. Hair is a characterisitic of mammals that is not shared with other animal phylum. Mammals contain mammary glands, which are used to feed milk to their offspring.