Across
- 5. Marie Curie and her husband discovered polonium and ____.
- 6. The lightbulb was invented by a famous scientist from _____.
Down
- 1. Marie Curie's research saved many wounded ____.
- 2. An apple falling from a tree made Isaac Newton think about _____.
- 3. the surname of the scientist who proposed the idea of "natural selection"
- 4. The speed of ____ always stays the same.