1. Starting around 7000 B. C., and for the next four thousand years, much of the Northern Hemisphere _____ temperatures warmer than at present.

2. Often very annoying weeds, _____ and act as hosts to many insect pests.

3. People in prehistoric times created paints by grinding materials such as plants and clay into powder _____.

4. Early forms of life on Earth, _____ in the absence of oxygen, required elements such as sulfur instead.

5. In the nineteenth century, Samuel Gridley Howe founded the Pekins School for the Blind, _____ for children in Boston, Massachusetts.

6. Often the design of a scholarly investigation _____ by the question it is addressing.

7. _____ ever developed was celluloid, a combination of natural camphor and cellulose nitrate.

8. Elizabeth Cabot Agassiz, _____ of Radeliffe College, had worked as both an educator and a naturalist.

9. Even though rhubarb is a vegetable, _____ as a dessert.

10. Mary Edmonia Lewis, a sculptor who studied at Oberlin College, was _____ by Hrrietffosmer.

11. The oldest city in the state, _____ .

12. Vaporization in connection with general _____ has a marked effect on long – term climate.

13. A biologist does not merely describe organisms, but tries to learn _____act as they do.

14. _____hardiness, daylilies can be cultivated particularly easily.

15. Resin is a substance that _____in water.