Why are lungfishes able to remove oxygen from the air?

Question

Why are lungfishes able to remove oxygen from the air?

Answer 1

because they have both lungs AND gills. Their lungs are often used when they hibernate (in the mud). the circulatory system of a lungfish is very complex due to the fact it has lungs and gills, it was very hard to find a picture of the anatomy of a lungfish but  here is a rough picture :

http://www.mbscientific.com/CircSysLungF...

the ventricle is a chamber of the heart and the atria is another part of the heart.

Answer 2

Because they evolved the ability to breath air so they could exploit oxygen poor pools of water as habitat.