What is the relationship between CO2 and O2 for urchins?

Sea urchins have a unique relationship of oxygen and carbon-di-oxide.

Explanation:

Sea Urchins spread oxygen in a unique way. They take in oxygen by staying inside water. Oxygen enters the body through their gills and tubed feet. CO2, which is waste is released through the anus. They get oxygen only through diffusion, i. e. diffusion of oxygen into the organism. Oxygen diffuses in body through the canals and carbon dioxide diffuses back into the canals. Urchins also have the capability to cope up with rising CO2 levels in the sea.