They are called ultraviolet rays, and they are what changes the appearance of the skin, like wrinkles and even cancer. ... During Antarctica's long, dark winter time, lower temperatures in the stratosphere cause ice crystals to form in the air. ... But the limitation would keep the problem from getting worse, they believe, and in time the ozone layer might rebuild itself (Fisher 37). ...

• Word Count: 1369
• Approx Pages: 5
• Has Bibliography
• Grade Level: High School

It is said that Mercury rotates three times for every two trips around the sun, so that during Planets 3 every alternate perihelon passage the same face points directly at the sun. " Geologically, the most remarkable features of Mercury are compressional cliffs or faults, just the sort of wrinkles that might form in the crust if the interior of the planet shrank slightly " (Morrison, 74, 1993). ... The surface is littered with winding channels that resemble river channels that have dried up over time. ...

• Word Count: 1722
• Approx Pages: 7
• Grade Level: High School