Which quotation from the text best suggests why al-Qaeda terrorists targeted the United States? A. “four more members of al-Qaeda’s crusade against Western ‘infidels’ departed
for San Francisco” (Paragraph 3)
B. “the passengers of Flight 93 stopped the plane from reaching the terrorists’
intended target — likely the White House or Capitol Building in Washington, D.C”
(Paragraph 8)
C. “these groups eventually found success tracking down and eliminating the
planners of the attacks, along with other rising terrorists.” (Paragraph 16)
D. “some critics charged that the CIA-supplied weapons also fell into the hands of
al-Qaeda and thereby aided the terrorists.” (Paragraph 17)

The Transformation of the World

Try to imagine what your life would be like without any machines working for you. Make a list of the machines in your household and on your person; you may arrive at a surprising number.

Now imagine earlier generations during their childhood years. How did they move from place to place? How did they communicate? What foods did they eat?

At one time, humans, fueled by the animals and plants they ate and the wood they burned, or aided by their domesticated animals, provided most of the energy in use. Windmills and waterwheels captured some extra energy, but there was little in reserve. All life operated within the fairly immediate flow of energy from the Sun to Earth.

Everything changed during the Industrial Revolution, which began around 1750. People found an extra source of energy with an incredible capacity for work. That source was fossil fuels — coal, oil, and natural gas, though coal led the way — formed underground from the remains of plants and animals from much earlier geologic times. When these fuels were burned, they released energy, originally from the Sun, that had been stored for hundreds of millions of years.

Coal was formed when huge trees from the Carboniferous period (345– 280 million years ago) fell and were covered with water, so that oxygen and bacteria could not decay them. Instead, the pressure of the weight of materials above them compressed them into dark, carbonic, ignitable rock.

Most of the Earth’s oil and gas formed over a hundred million years ago from tiny animal skeletons and plant matter that fell to the bottom of seas or were buried in sediment. This organic matter was compacted by the weight of water and soil. Coal, oil, and gas, despite their relative abundance, are not evenly distributed on Earth; some places have much more than others, due to geographic factors and the diverse ecosystems that existed long ago.

Early Steam Engines

The story of the Industrial Revolution begins on the small island of Great Britain. By the early 18th century, people there had used up most of their trees for building houses and ships and for cooking and heating. In their search for something else to burn, they turned to the hunks of black stone (coal) that they found near the surface of the earth. Soon they were digging deeper to mine it. Their coal mines filled with water that needed to be removed; horses pulling up bucketfuls proved slow going.

The Transformation of the World

Try to imagine what your life would be like without any machines working for you. Make a list of the machines in your household and on your person; you may arrive at a surprising number.

Now imagine earlier generations during their childhood years. How did they move from place to place? How did they communicate? What foods did they eat?

At one time, humans, fueled by the animals and plants they ate and the wood they burned, or aided by their domesticated animals, provided most of the energy in use. Windmills and waterwheels captured some extra energy, but there was little in reserve. All life operated within the fairly immediate flow of energy from the Sun to Earth.

Everything changed during the Industrial Revolution, which began around 1750. People found an extra source of energy with an incredible capacity for work. That source was fossil fuels — coal, oil, and natural gas, though coal led the way — formed underground from the remains of plants and animals from much earlier geologic times. When these fuels were burned, they released energy, originally from the Sun, that had been stored for hundreds of millions of years.

Coal was formed when huge trees from the Carboniferous period (345– 280 million years ago) fell and were covered with water, so that oxygen and bacteria could not decay them. Instead, the pressure of the weight of materials above them compressed them into dark, carbonic, ignitable rock.

Most of the Earth’s oil and gas formed over a hundred million years ago from tiny animal skeletons and plant matter that fell to the bottom of seas or were buried in sediment. This organic matter was compacted by the weight of water and soil. Coal, oil, and gas, despite their relative abundance, are not evenly distributed on Earth; some places have much more than others, due to geographic factors and the diverse ecosystems that existed long ago.

Early Steam Engines

The story of the Industrial Revolution begins on the small island of Great Britain. By the early 18th century, people there had used up most of their trees for building houses and ships and for cooking and heating. In their search for something else to burn, they turned to the hunks of black stone (coal) that they found near the surface of the earth. Soon they were digging deeper to mine it. Their coal mines filled with water that needed to be removed; horses pulling up bucketfuls proved slow going.