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]
Stress. Children experience stress as a normal part of growing and learning. Stress is any external stimulus that threatens the balance of the normal equilibrium in the body. It can result from positive as well as negative experiences. The events or experiences that cause stress are known as stressors.