1. The hermit crab, a crustacean that uses an empty shell as a portable refuge to cover its soft abdomen, changes shells as grows.

2. In the mid-1960's many artists began to working outdoors on a large scale, making the landscape rather than the studio their arena.

3. Electoral politics in the United States has been dominated by two political parties since the administer of George Washington.

4. Art Deed, a style of design popular in the 1920's and 1930's, was used primarily in furniture, jewel, textiles, and interior decoration.

5. Initially introduced in 1852, the gyroscope consists a spinning device, usually in the form of a wheel, that exhibits strong angular momentum.

6. The membrane surrounding a single-celled animal or plant or any individual cell in a multicellular organism is important in the respiratory and nutritionally processes of that cell.

7. In the nineteenth century, moving from crowded Britain to relatively sparsely populated North America were seen by many British as an act of patriotism.

8. The Fourth Amendment to the Constitution of the United States regulates the right of the government to search a citizen's personal and property.

9. The color and pageantry, keen rivalry, and high level of competition both contribute to the great worldwide interest in the Olympic Games.

10. Although have there been better singers and actresses than Ethel Waters, none typifies the rise from rags to riches more dramatically than she.

11. The college that became Harvard University, the oldest institution of higher learning at the United States, was founded in Cambridge, Massachusetts, in 1636.

12. In a eclipse of the Sun, the regions of umbra experience total eclipse and those of penumbra, partial eclipse.

13. Paleoanthropologists examine fossil remains of extinct primates, while physical anthropologists concern with ethnology study the behavior of primates in their natural settings.

14. Most ocean waves are generated by wind current that agitate the water's surface.

15. Some seeds are viable, or capable of growing into healthy plants, for only a few days after fall from the parent tree.

16. Statistics indicate that approximate every 22 years--within a range of 3 to 4 years--a major drought occurs in the United States.

17. The work of Sarah Oarne Jewet, care-nineteenth-century writer, reflects a concern in the alienating consequence, of condustrialization and urbanization.

18. Seismic waves generated by an earthquake or large explosion can be recorded thousands of kilometer from their source.

19. After the United States became independent, the cure of more fertile lands drew steadily New Englanders into the Ohio Valley and the British colony of Upper Canada.

20. Found in all oceans the various species of electric rays use the charge they can generate for both stunning prey or warding off predators.

21. Barium is a soft, heavy, silvery white metallic element that readily reacts with another elements to form useful compounds.

22. Among the most complex crystals are that of silicon dioxide, which has seven different structures at various temperatures and pressures, the most common being quartz.

23. Animals have to cope with and control physical and chemical processes that do not necessarily act to benefit of the animal.

24. By 1810 the 23 towns of Hampshire County, Massachusetts, had reached a remarkable uniform of economic development as well as population density.

25. With more than half the world's annual yield of 50 million tons of soy beans, an important source of protein, is grown in the United States.