6. What is a gill?
- Part of the cephalon that breaks away from the skeleton during ecdysis.
- Feathery structure used for gas exchange that is positioned above the legs.
- For locomotion
7. What section of a Trilobite is the cephalon?
- Top
- Middle
- Bottom
8. What is the term for the process where a trilobite sheds its exoskeleton?
- Secretion
- Ecdysis
- Bleaching
- Siphon
9. When did trilobites first come about?
- 540 million years ago
- 260 million years ago
- 180 million years ago
- 600 million years ago
