1. The geographic position of North America, ________ in the early days of the European settlement.

2. Often a team of engineers are ________.

3. Most insurance agents would rather you ________ anything about collecting claims until they investigate the situation.

4. Only one mammal, ________ is known to bear routinely four identical young.

5. The Appalosa horse was brought to Mexico from Spain, was later 0introduced into the United States, and today ________.

6. Cuba is ________sugar-growing areas in the world.

7. Not every pearl that is found ________.

8. The bacteria in milk is destroyed when ________ to at least 62¦C.

9. The growth of two-income families in the United States ________ of people moving to a new social class.

10. Although it is difficult ________ , a frog is more likely to be smooth and wet, and a toad rough and dry.

11. ________ fall naturally into two classes, which can be further subdivided into several subclasses.

12. Not until the Triassic Period ________.

13. ________ planet from the sun, Mars, has a year of 687 days.

14. The city council is empowered not only to enact new laws, ________ select a new mayor between elections should the need arise.

15. A giant kind of grass, bamboo may reach a height of 120 feet and ________.

16. The sea mammal medusa is popularly called a jellyfish because it ________ jelly.

17. The tallest bird on the North American continent, the white whooping crane, ________ four and a half feet tall.

18. ________ extensively by persons who cannot speak or hear, American Sign Language ranks as the fourth most widely used language in the U.S. today.

19. In the seventeenth century, North America was vast and unconquered, ________ only at great cost.

20. By the twenty-first century, the computer ________ a necessity in every home.