1. The concept of number and the counting process developed so long before the time of recorded history  that the manner of this development is largely conjectural.

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

3. 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.

4.  An assortment of vocal sounds was developed as a word tally against the number of objects in a small group.

5. It was pounded meticulously and mixed with water to make it entirely even in texture.

6. Some pots were adorned with incised or stamped decorations.

7. Further burial and slow cementation—a process by which crystals become bound together in a mosaic of intergrown ice crystals—finally produce solid glacial ice.

8. The consistency of the clay was crucial: it was pounded meticulously and mixed with water to make it entirely even in texture.

9. Further burial and slow cementation—a process by which crystals become bound together in a mosaic of intergrown ice crystals—finally produce solid glacial ice.

10. The snow is usually many meters deep by the time the lower layers art converted into ice.

11.  They were apparently subjugated in southern Mesopotamia by the Sumerians,

12. They were apparently subjugated in southern Mesopotamia by the Sumerians, whose name became synonymous with the region immediately north of the Persian Gulf,

13. But it was not until the 1890’s that archaeologists excavating in city-states well to the south o fNieveh found many thousands of tablets inscribed in Sumerian only.

14. The glacier had formed as layer upon layer of snow accumulated year after year.

15. drilling into the ice was tantamount to drilling back through time.

16. The result is a remarkable unbroken record of temperature and of atmospheric levels of carbon dioxide.

17. There is indirect evidence that the link between carbon dioxide levels and global temperature change goes back much further than the glacial record.

18. A second, more dense atmosphere, however, gradually enveloped Earth as gasses from molten rocks within its hot interior escaped through volcanoes and steam vents

19.  With much of the water vapor already condensed into water and the concentration of carbon dioxide dwindling, the atmosphere gradually became rich nitrogen.

20.  At any rate, plant growth greatly enriched our atmosphere with oxygen.

21. The dissolved rock and carbon dioxide eventually flow into the oceans, where they precipitate to form new terrestrial rocks, often with the help of life-forms

22.  We now have some evidence that the symbolism used in masks is often universal.

23.Coding schemes were developed to enable researchers to compare the detailed facial positions of individual portions of the face (eyebrows, mouth, etc.) for different emotions

24. As suspected, the twp sets of masks had significant differences in certain facial elements.

25. Natural selection has acted in a variety of ways in different species to enhance the efficacy of the behaviors,

26.  In some species, like the European hare, erratic zigzag flight might be more effective in the presence of predators that are faster than they are and straight flight more effective against predators that are slower.

27. The alarmed prey flees for a short distance and then “freezes.” Some predators are unexcited by immobile prey, and a startling flash of activity followed by immobility may confuse them.

28.  “Flash” behavior is used in particular by frogs and orthopteran insects, which make conspicuous jumps and then sit immobile.

28. An era when polished stone implements and bows and arrows were already being used and dogs had already been domesticated.

29.  There is evidence that humans hunted these elephants, as shown by numerous spear points found with mammoth remains.

30. It proved how much harm was done by the uncontrolled, reckless use of insecticides. 

31. At the time, spokesmen for the chemical industry mounted personal attacks against Carson and issued propaganda to indicate that her findings were flawed. 

32. Like Montgomery, the heroine of the book is taken in by an elderly couple who lives in the fictional town of Avonlea.

33. It was her first efforts that secured her prominence, and the Anne books are still read all around the world.

34. Her novels have helped create a warm picture of Prince Edward Island’s special character.

35. The rise of the US. steel industry in the last quarter of the 19th century was brought about largely by the demand for Bessemer steel rails for the nation’s burgeoning rail network. 

36.  Steel rails were far more durable than those made of iron. Spurred by this demand, the us. steel industry became the largest in the world in 1886, when it surpassed that of Great Britain.

37.  Because sea otters are picky eaters, each animal preferring only a few food types. Thus no single type of food source is exhausted.

38. Sea otters keep warm by means of their luxuriant double-layered fur, the densest among animals. 

39. While elated by the otters return, scientists are concerned about the California sea otter population growth of 5% a year, lagging behind the 18% a year rate among Alaska otters. 

40. Since surface finishes provided a pleasing appearance and also improved the durability. In day-to-day use, the potter smoothed the exterior surface of the pot with wet hands. `