Read the paragraph. Then answer the questions that
follow.
Scientists have long been fascinated by the way
massive rocks move along tidal beaches in the Arctic Sea.
NASA advisor and physics scientist Ralph Lorenz had read
stories about how large rocks encased in ice move along
tidal beaches in the Arctic Sea. He theorized that something
similar might be happening in Death Valley, causing rocks
as heavy as 700 pounds to glide across the sand. To test his
theory, he filled a container with water, placed a rock in the
water, and froze it. He placed the ice-encased rock in a tray
of water with sand at the bottom and blew on the rock. It
moved across the sand easily and left a visible trail in the
sand. He suggested that moisture in the air collects under
rocks and freezes at night when the temperature in Death
Valley plummets. The ground under the rock becomes
muddy, so when the winds blow, the ice on the rock makes it
skid across the wet ground, leaving a trail in its wake. Using
his observations of the rocks that move along the tidal
beaches in the Arctic Sea, Lorenz was able to prove similar
movements of rocks in Death Valley through a fairly easy
experiment.
Read the sentence from the paragraph.
The ground under the rock becomes muddy, so when the
winds blow, the ice on the rock makes it skid across the wet
ground, leaving a trail in its wake.
The writer wants to revise the sentence to help the reader
better understand Lorenz's theory. Which of these revisions
best accomplishes this task?
A) Muddy rocks turn icy, and the wind can blow across
the sand, leaving a trail behind them.
B) The rocks covered in ice glide in the wind on hot days
across wet sand that has been made soft by melting
ice.
C) The ground under the rock becomes muddy as the
wind blows and ice melts. The rocks left covered in
ice skid over other rocks that leave trails as they slide
along the ground.
D) The frozen moisture under the rock melts on hot
days, making the ground muddy. The ice-covered
rock leaves a trail behind it as it skids over the wet
ground when the wind blows.
