1.   A tornado develops when the motion in large slowly rotating thunderstorms is concentrated into a narrow violent swirl.

2.   A tornado develops when the motion in large, slowly rotating thunderstorms is concentrated into a narrow violent swirl.

3.   But if the star is large to begin with, so much mass becomes concentrated into so small a volume that a threshold is passed.

4.   It is expected that artificial emissions would be concentrated into a far narrower wavelength than that observed.

5.   That means the birds overwintering in the Southern Hemisphere are concentrated into much smaller areas than they are in North America during the summer.

6.   The shifting wind in the vertical, called wind shear, helps provide the twisting motions that can be concentrated into a tornado.

7.   The shifting winds in the vertical, called wind shear, can help provide the twisting motions that can be concentrated into a tornado.

8.   The shifting winds in the vertical, called wind shear, can provide the twisting motions that can be concentrated into a tornado.

9.   Pollutants from industrialized areas of Asia may be concentrated into the atmosphere there, damaging the delicate chemical balance that maintains the ozone content.

10.   Most are concentrated into a space of only a few city blocks.