Murray Snyder, age 7, of Toronto, Ontario, Canada, for his question:

How did the dinosaurs die out?

The giant dinosaurs lived on the earth for more than 100 million years. Then quite suddenly they started to die out. In just a few thousand years, not one of them was left. Nobody can say for sure how they were wiped out. Perhaps the worldwide weather changed and the dinosaurs found it too hot or too cold, too damp or too dry. Perhaps they were wiped out by some strange disease. Perhaps they ate up all their food and starved to death. Another theory is that a  giant asteroid struck the earth creating a large cloud of dust the cut out the sun and thus plants their source of food died out.   At present, nobody knows the answer for sure.