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!

Respiratory pigments are able
to carry and other respiratory
present in circulatory .

In crustaceans and arachnids
hemocyanin is respiratory pigment.
In the analogous pigment
hemoglobin.