Question

cracking up
1 a group of nomads got a shock recently when out in a desert in ethiopia, a crack of
lightning split the ground into parts, sending a mountain high. the men screaming, the
camels disappeared. water then fled from the ground behind them.
2 the event didn’t last any milliseconds. it was just one in a geological process that is
slowly turning east africa into ocean, africa.
3 earth’s crust is made up of tremendous plates that fit together like pieces in a jigsaw puzzle.
called tectonic plates, the plates are moving very slowly. some plates are crashing together
while others are pulling apart. in the long course of earth’s history, the movements of plates have created mountains, oceans, and
continents.
4 in eastern africa, two huge tectonic plates — the african plate and the arabian plate — are pulling away from each other.
“these are two plates spreading apart on land,” says david adede, an earth scientist at the university of benin in benin city,
nigeria, africa.
5 that’s not all. as the two plates pull apart, the african plate is splitting into two pieces. leaving
a great rift (gap) in between them. what was once one tectonic plate is now becoming two plates.
6 recently, that volcanic activity has gotten dramatic. in 2005, the cracking of the african plate
caused a colossal depression in ethiopia. that was followed by a series of earthquakes that came
with the seismic belt. the earthquakes occurred as magma (liquid rock) rose from deep within
the earth, splitting the ground wide open. a series of cracks, some as wide as 10 feet, opened along
a 35 - mile stretch of desert in ethiopia. since then, the cracks have continued to grow.
7 africa’s tectonic activity has been going on for 30 million years. the spreading and cracking is what formed the red sea, as
well as a deep depression known as the great rift valley. the rift zone runs from the bottom of the red sea through eastern
africa.
8 as the two sides of the rift valley pull even farther apart, the entire area will eventually fall below sea level. eventually, water
from the red sea will rush in to fill the rift, spawning a new body of water. a million years from now — probably sooner — the
great rift valley will be at the bottom of an ocean that divides africa in two.

endnote

1. which statement best expresses a central idea of the text?

• nomads are people who live in and wander throughout ethiopia.
• tectonic plates can move under the ocean and on land.
• over millions of years, the movement of tectonic plates have formed earth’s landscape.
• tectonic plates spreading apart in africa will eventually create a new ocean.

1. paragraphs 4 and 5 support which of the following claims?

a. experts have discussed the movement of tectonic plates in africa
b. an unexpected earthquake shocked many of the people living in ethiopia.
c. the spreading of tectonic plates in africa is pulling the continent apart
d. tectonic plates are the pieces of the earth’s crust that fit together like a puzzle.

Explanation:

1. For the first question, the text focuses on how tectonic plates in Africa are spreading, which has formed landforms like the Great Rift Valley and will eventually create a new ocean. This is the overarching central idea that ties together the details about plate movement, past activity, and future changes.
2. For the second question, Paragraphs 4 and 5 explicitly state that two tectonic plates in eastern Africa are pulling away from each other, and the African Plate is splitting into pieces as this happens, which directly supports the claim about the plates pulling the continent apart.

Answer:

1. Tectonic plates spreading apart in Africa will eventually create a new ocean
2. c. The spreading of tectonic plates in Africa is pulling the continent apart