Aquatic Oxygen Use

How do animals get their oxygen under water? Drag a number to the circle to match the aquatic use of oxygen by each species.

Each number can match all circles, but this is not a correct solution. This app does not grade itself. Translated from Danish: [url=http://www.geogebra.org/caro0673]caro0673[/url] — September 17, 2013 - 5:36 PM