Rivers exchange water, materials, energy, and nutrients, in a reciprocal manner with the surrounding environment. River water quality, sediment characteristics, and biological communities, all reflect characteristics of the upstream, and even the downstream environment.aintaining position in the face of flow can be energetically costly, but provides access to a conveyer belt-like food-delivery system. Stream and river organisms reflect their localized niche, and surrounding landscape both upstream and downstream.
In a merger announced on March 5, 2006, and executed on December 29, 2006, AT&T Inc. (originally SBC Communications) acquired BellSouth for approximately $86 billion (1.325 shares of AT&T for each share of BellSouth).
With the rapidly growing number of telephone customers, AT&T and Bell Labs develop the North American Numbering Plan, a system that assigns telephone numbers to customers in the United States and its territories as well as Canada and many Caribbean nations.irst phone to combine a ringer and handset. AT&T introduces the Model 500 telephone, the first that combines a ringer and handset. The classic black rotary phone, featuring an adjustable volume control for the bell and later a variety of colors, becomes a cultural icon.