1) Sociologists have long recognized that social tension _____.

2) _____ have a very keen sense of hearing, although most do not hear sounds audible to the human ear.

3) Although both political parties wanted Dwight D. Eisenhower as their presidential nominee in 1952, he became a Republican candidate and _____.

4) If an act is rewarded many times, immediately and with strong reinforces, it will rapidly become _____.

5) Color and light, taken together, _____ the aesthetic impact of the interior of a building

6) ______ planes in flight between airports, air traffic controllers rely on radar.

7) The operating principles of the telephone are ______ they were in the nineteenth century.

8) Steel magnate Andrew Carnegie used part of his wealth _______ more than 2,500 public libraries in Englishspeaking countries between 1881 and 1919.

9) Not until 1949 _______ Canada’s tenth province.

10) Paul Samuelson revolutionized _____ by presenting his students with the most advanced economic thinking at an introductory level.

11) The scholarly interest in perception stems largely from questions about the sources and validity of what _____ .

12) Because of the Aleuts’ constant exposure to cold weather, they have long recognized _____ .

13) Almost all economists agree _____ by trading with one another.

14) The development of mechanical timepieces spurred the search for _____ with which to regulate them

15) Anthropology is a science _____ anthropologists use a rigorous set of methods and techniques to document observations that can be checked by others.