11.   He thinks they might have spent years trapped in polar ice before re-emerging to strike again.

12.   How much we gardeners have commiserated about the unnaturalness of year-round temperatures that heat oceans and melt polar ice.

13.   Join the world of Internet expeditions, and you can slog through polar ice in the comfort of your pajamas.

14.   Now, of course, Mars is dry as a bone, except for some permafrost and polar ice.

15.   Optimists in a land synonymous elsewhere with winter gloom, Greenlanders have chosen as their national flag a red sun rising over white polar ice.

16.   Scientists said the descriptions by McCarthy and McKenna focused new attention on the collection and analysis of more data about polar ice conditions.

17.   Speaking last week in Spokane he talked of a new United Nations report that warned of rapid temperature increases and melting polar ice.

18.   The average thickness of polar ice during the summer months is believed to be a bit more than six feet.

19.   The possibilities are riveting to specialists across the sciences, from experts in plant migration to researchers who peek inside polar ice cores for clues about prehistoric climate.

20.   The polar ice melted, and the deep-ocean circulation in turn slowed down, creating a brief respite from extinctions before the whole cycle repeated itself.