| 1. Scientists can determine a person's sex, age, and race by _______________ a single strand of hair. | | |
| 2. No matter what a star's _______________ is, it will eventually run out of usable fuels. | | |
| 3. On the average, more animals are killed by _______________ than by hunters with guns. | | |
| 4. Tooth enamel is the hardest _______________ manufactured in the human body. | | |
| 5. _______________ human settlements in Rwanda have driven out or destroyed much of the country's wildlife. | | |
| 6. The shooting star _______________ across the sky. | | |
| 7. Many people in Somalia _______________ their age by the number of wet seasons they have lived through. | | |
| 8. Seaweed is a general term for more than 20,000 _______________ of sea plants living in the world's oceans and seas. | | |
| 9. A planet circling the sun has a certain amount of _______________ momentum. | | |
| 10. Due to _______________, for a few weeks each year, the mountain known as K2 is actually higher than Mt. Everest. | | |
| 11. Frank is the head of the team that is trying to come up with a new marketing strategy, but the real _______________ behind the project is Sylvia. | | |
| 12. David Suzuki notes that from our first cry announcing our arrival on Earth to our very last sigh at the moment of death, our need for air is _______________. | | |
| 13. The Republic of Kyrgyzstan suffered a period of confusion and violence as the Soviet Union _______________. | | |