The answer is:
Echinodermata
The word echinodermata is Greek which literally means "Spiny Skin". Echinodermata is a phylum under kingdom animalia. Not all of them have spiny skins, but most of them do. Other characteristics would be their radially symmetric body. They have appendages that grow outward from the center. Examples of echinoderms would be sea stars and sea urchins.
Because carbohydrates can be converted into energy but can not store energy.
Answer: this is called passive transport and it does not require energy.
Some arteries carry oxygenated blood just as some capillaries do.
Some veins carry deoxygenated blood just like some capillaries do.