11. What is the difference
between gills and lungs?

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
Gills and lungs richly vascularized
organs serve for gas
between the environment the
circulatory system.

lungs differentiate from in that
they saclike structures always
to the organism specialized
in gas in terrestrial
environment. , in their turn,
internal or external
structures in direct with water
and in gas exchange
aquatic environment.