How does oxygen enter the urchins system?

Enters through the gills and tubed feet.

Explanation:

The oxygen obtained by a Purple Sea Urchin is dissolved in water.  Oxygen enters through the gills and tubed feet. When the oxygen level is low in a Purple Sea Urchin, muscles associated with Aristotle's Lantern pump fluid through the body (through the canals).

Any Questions?

glycolysis is a process that fuel your metabolism. it is apart of cellular respiration the process that produce atp.

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.