2. Created by Science Teachers Unit 4 Lesson 2-4

3. 100 200 400 300 400 ChangesTimeForcesAgents 300 200 400 200 100 500 100

4. Row 1, Col 1 The carrying away of materials from one place to another What is erosion?

5. 1,2 The study of trees that help find clues about the tree’s past What is dendrochronology?

6. 1,3 The kind of weather and surroundings in which trees have grown What is environmental condition?

7. 1,4 A colorless, odorless gas that is present in the atmosphere and is formed when any fuel containing carbon is burned What is carbon dioxide?

8. 2,1 Colorless, odorless Tasteless gas (Humans breathe in) What is oxygen?

9. 2,2 Ring located in the center of a tree’s trunk that tells the age and environmental conditions from present to past What is a tree ring?

10. 2,3 A dark spot in the tree’s rings that tell whether the tree has been damaged by fire or insects What is a scar?

11. 2,4 Rings located in the center of a tree’s trunk that tells the age and environmental conditions from present to past What is a tree cookie?

12. 3,1 Repeated sequence Of events (Ex. Water cycle, Rock cycle, life cycle, nitrogen cycle) What is a cycle?

13. 3,2 The remains of any organism from the past What is a fossil?

14. 3,3 Imprinted fossil preserved in a rock What is track?

15. 3,4 An event that happens in a specific order What is sequence?

16. 4,1 When items are stacked on top of one another, the layers on the bottom are older than the layer on top What is superposition?

17. 4,2 Hint of information that can help someone What is a clue?

18. 4,3 No longer in existence What is extinct?

19. 4,4 In danger of becoming extinct What is endangered?

20. 5,1 Rock that changes into a different type of rock by pressure and heat What is metamorphic rock?

21. 5,2 Rock that is formed from the compacting of sediments What is sedimentary rock?

22. 5,3 The continuous series of changes that rocks undergo What is a rock cycle?

23. 5,4 The breaking down and wearing away of rock material What is weathering?