Across
- 4. without echo
- 5. echoes are brighter
- 6. the act of spreading outward from a central source
- 8. an unborn vertebrate in the later stages of development
- 9. high frequency sound waves
Down
- 1. a bodily organ that is essential for life
- 2. fluid collection within the body
- 3. similar echo patterns
- 7. an electrical device that converts one form of energy into another