6. What is the external rigid carapace of arthropods called? Of which substance is it made? Which type of organic molecule is that substance?
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!