Noreen Orlowski, age 12, of Bridgeport, Conn. For her question:

When did the Rocky Mountains form?

The proud Rockies started to grow about 100 million years ago and reached their full height saome 50 million years later. As mountains go, they are mere teen agers. When they were born, the Sierra Nevadas were already grown and the eastern Appalachians were old timers.

The Alps and the Pyrermes of Europe are youngsters of about 50 million years. The high Himalayas, loftiest peaks in the world, are also young mountains and still growing.