1.As a consequence, they are perhaps the best group of  insects for examining patterns of terrestrial biotic diversity and distribution

2. Perhaps the aspect of butterfly diversity that has received the most attention over the past century is the striking difference in species richness between tropical and temperate regions.

3. The total number found on the British islands did not exceed 66, and the whole of Europe supported only 321.

4. It is hoped that by focusing on them, the errors generated by imperfect and incomplete taxonomy will be minimized.

5. The Egyptians made coarse fibers by 1600 B.C., and fibers survive as decorations on Egyptian pottery dating back to 1375 B C.

6. the fibers were brittle, ragged, and no longer than ten feet, the circumference of the largest reels.

7. Glass fibers were little more than a novelty until the 1930’s, when their thermal and electrical insulating properties were appreciated and methods for producing continuous filaments were developed.

8. Deep dives are less dangerous if helium is substituted for nitrogen, because under these pressures helium does not exert a similar narcotic effect.

As a scuba diver descends, the pressure of nitrogen in the lungs increases. Nitrogen then diffuses from the lungs to the blood and from the blood to body tissues

10. This change in volume may cause the lungs to distend and even rupture.

11. Advocates of organic foods – a term whose meaning varies greatly – frequently proclaim that such products are safer and more nutritious than others.

12. There are numerous unsubstantiated reports that natural vitamins are superior to synthetic ones.

13. In many cases consumers are misled if they believe organic foods can maintain health and provide better nutritional quality than conventionally grown foods.

14. In the seventeenth century the organ, the clavichord, and the harpsichord became the chief instruments of the keyboard group, a supremacy they maintained until the piano supplanted  them at the end of the eighteenth century.

15. A supremacy they maintained until the piano supplanted them at the end of the eighteenth century.

16. They  produced an instrument capable of myriad tonal effects from the most delicate harmonies to an almost orchestral fullness of sound, from a liquid, singing tone to a sharp, percussive brilliance.

17. There is archaeological evidence that counting was employed by humans as far back as 50,000 years ago although the manner of this development is largely conjectural.

18. Probably the earliest way of keeping a count was by some simple tally method, employing the principle of one-to-one correspondence.

19. Counts could also be maintained by making scratches in the dirt or on a stone, by cutting notches in a piece of wood, or by tying knots in a string.

20. later, an assortment of vocal sounds was developed as a word tally against the number of objects in a small group.

21. The best-known specimens are the remarkable tracks discovered at Lactoli, Tanzania, by Mary Leaky.

22. The pressures exerted along the foot, together with the length of stride, which averaged 87 centimeters, indicated that the hominids had been walking slowly

23. The study of fossil footprints is not restricted to examples from such remote periods.

24. The motivation derived from the text, and in the case of singing, the music, in combination with the performer’s skills, personality, and ability to create empathy.

25. How a speaker perceives the listener’s receptiveness, interest, or sympathy in any given conversation can drastically alter the tone of presentation.

26. Emotional health is evidenced in the voice by free and melodic sounds of the happy, by constricted and harsh sound of the angry, and by dull and lethargic qualities of the depressed.

27. When the United States became an independent nation in 1776, it did not have a single city as large as 50,000 inhabitants, but by 1820 it had a city of more than 10,000 people, and by 1880 it had recorded a city of over one million.

28. It was not until after 1823, after the mechanization of the spinning had weaving industries, that cities started drawing young people away from farms.

29. Modern comparisons of the amount of work performed per week, however, begin with the Industrial Revolution (1760-1840) when 10- to 12-hour workdays with six workdays per week were the norm.