They operate at all levels: national, state, county/district/parish, city/town/village. They even operate internationally.
Unfunded mandates states that the federal order that states operate and pay for a program created at the national level. The balance between national powers and state have changed greatly since the Constitution was written.
Usually, national organizations have groups at the state and local levels. The national organization would coordinate with the state levels, who would in turn coordinate with the local levels.
Sea level pressure, sometimes as mean sea level pressure.
imagine a bouncing castle on cellular level. by absorbing water through osmosis a cell keeps its inner pressure at a certain level so that a system of cell "balloons" can support a plant structure. and when a plant dries out, it shrivels and looses its shape
A pressure switch reads pressure not level.
Water level in all pressure canners should be 2-3 inches with the jars in place to operate safely and effectively. Be careful not to overfill the canner, sufficient head-space must be maintained for the canner to work safely.
High level
Interest groups exist nationwide, in nearly all countries. These groups look out for the interests of big corporations and companies, primarily. They may say they operate for employee interests, but it's much bigger than common folks. In medical areas, interest groups fight to keep medical reimbursements (payments) at a profitable level or to keep or get more research monies. All these do trickle down to common folks, but still, the interest group is more interested in the macro level of economics rather than the micro level that affects ordinary citizens.
Sea level pressure.
the atmospheric pressure below sea level is highter (novanet)
Interest groups can operate at all levels of the government ranging from federal to local governments. An interest group can be a civil rights group, a charitable organization, or simply a neighborhood association.
Many influential lobby groups inhabit the halls and offices of Congress. Some of them include the National Rifle Association, the US Chamber of Commerce, the American Medical Association, and Exxon Mobil.