Streams In performing research for an ecology class,students at a college in upstate New York collect data on streams each year. They record a number of biological, chemical, and physical variables,...

Streams In performing research for an ecology class,students at a college in upstate New York collect data on streams each year. They record a number of biological, chemical, and physical variables, including the stream name, the substrate of the stream (limestone, shale, or mixed), the acidity of the water (pH), the temperature (°C), and the BCI (a numerical measure of biological diversity).