Science Weekly back issues from April 1999:
Science Weekly.(dams)
Apr 16, 1999 ... Dams A flood can occur after a very heavy rain or after too much melting snow. Some rivers overflow their banks. The rushing water can cause a lot of damage. Dams are built across rivers. They help control how much and how fast the river water flows. Slowly, a dam releases water ...
Coral Reefs.
Apr 30, 1999 ... Coral reefs are often called the "rainforests of the sea." Do you know why? Both coral reefs and rainforests are ecosystems-communities of plants and animals that live together in harmony. Both are colorful worlds filled with thousands of different kinds of plants and animals - so many ...