Across
- 2. : the moment when two objects hit each other
- 4. a set of interacting parts forming a complex whole
- 5. : when something becomes different over time
- 7. : a group of atoms joined together in a particular way
Down
- 1. : tiny organisms that are made of a single cell
- 3. : to reach a conclusion using evidence and reasoning
- 4. : a small part that is meant to show what the whole is like
- 6. : water that is underground