Total natural gas rig count in the US (including conventional gas drilling) Shale gas is natural gas that is found trapped within shale formations. Shale gas has become an increasingly important source of natural gas in the United States since the start of this century, and interest has spread to potential gas shales in the rest of the world.
A stressor is a chemical or biological agent, environmental condition, external stimulus or an event that causes stress to an organism.[1]
Medical Definition of STRESS. 1. a: a force exerted when one body or body part presses on, pulls on, pushes against, or tends to compress or twist another body or body part; especially: the intensity of this mutual force commonly expressed in pounds per square inch b: the deformation caused in a body by such a force.