Across
- 7. circulatory system/a system in which blood is always pumped throughout the body
- 8. internal skeleton made of bone and cartilage
- 10. hard, external, supporting structure that develops from the ectoderm
- 11. digestive tract
- 12. circulatory system/a system in which a fluid in a cavity called the hemocoel bathes the organs directly with oxygen and nutrients
- 13. vascular system/the networks of blood vessels within the organism
Down
- 1. part of a larger structure, such as the body of an organism, that is set off by natural or arbitrary boundaries
- 2. phase in the life cycle of many animals during which a rapid change from the immature organism to the adult takes place; an example is the change from larva to adult in insects
- 3. animal that does not have a backbone
- 4. mass of nerve cells
- 5. eye composed of many light detectors separated by pigment cells
- 6. body cavity that contains internal organs
- 9. feeler that is on the head of an invertebrate, such as a crustacean or an insect, and that senses touch, taste, or smell