01 . Essentially,a theory is an abstract, symbolic representation of what is conceived to be reality.
02. Thanks to modern irrigation, crops now grow abundantly in areas where once nothing but cacti and sagebrush colud live.
03. Anthropolgists have discovered that fear, happiness ,sadness, and surprise are universally reflected in facial expressions.
04. Of the millions who saw Haley's Comet in 1996, how many people will live long enough to see it return in the twenty-first century.
05. The greater the population there is in a locality , the greater the need there is for water,transportation,and disposal of refuse.
The greater the population there is a locality, the greater the need there is for power,fossil fuel and greenhouse gas discharging level.
06. Perfectly matched pearls,strung into a necklace, bring a far higher price than the same pearls sold individually.
07. The development of mechnical timepieces spurred the search for more accurate sundials with which to regular them.
08. Studies of the gravity field of the Earth indicate that its crust and mantle yield when unusual weight is placed on them.
09. Quails typically have a short rounded wings that enalbe them to spring into full fight instantly when disturbed in their hiding places.
10. Fungi are imprtant in the process of decay, which returns ingredients to the soil, enhances soil fertility, and decomposes animal debris.