Answer to Question 1 Gas taken from a well must be cleaned in an extraction unit. This unit removes impurities such as water, sulfur,
and dust.
At the processing plants, butane, propane, and gasoline are removed from the gas.
The finished gas is then fed into a transportation pipeline where it is compressed to about 1,000 pounds per
square inch. It travels through the pipeline at up to 15 miles per hour.
When it reaches a city, distribution lines carry it to the consumers.
The consumers receive the gas from individual service lines connected from the main lines. The United States
has about 1 million miles of gas lines in operation.
Answer to Question 2 Natural gas is measured and sold in one of two different units: by volume and by heat.
In most of the world, natural gas is measured in cubic meters. The most common unit in the United States is
cubic feet. To account for the effect of pressure, the unit of measure for natural gas is measured at the pressure
of the atmosphere at sea level.
The other common unit of measure is the British thermal unit (or BTU). A BTU is defined as the amount of
heat required to raise the temperature of 1 pound of water by 1 degree Fahrenheit.
Three principle forms of natural selection: (a) stabilizing selection, (b) directional selection, an
Increasing Costs of Natural Disasters
Major steps in the coagulation cascade
Steps in the humoral and cell-mediated immune responses.
Steps involved in charging tRNA
Proposed steps in the evolution of jaws