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	<question>
		<phrase isaudiomp3="1" mp3="AUDIO_REPOS/1.0.mp3"></phrase>
		<question isaudiomp3="1" rationale="0" picture="images/question1.jpg" mp3="AUDIO_REPOS/2060-1" exercise_type="" questionmode="" choicemode="" answerbankid="" answerbankmode="" rationalemode="" playonload="" mp3speed="" ttsspeed="" passage="1" show_passage="" show_passage_audioplayer="" passage_audio_type="" showvideo="" video="" enable_audio_recorder="" recorder_mode=""><![CDATA[]]></question>
		<saythis><![CDATA[]]></saythis>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[LOS ANGELES  -  Scientists who study planets dream of sending a geologist to Mars to inspect its rocks by hand.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[Until then, they have to settle for examining meteorites  -  chunks of the Red Planet that land on Earth after hurtling through space.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[Though a little banged up after their fall through the atmosphere, these meteorites provide a lot of information.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[But it can be hard for geologists to interpret what they see when they can't agree on how old a rock is.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[And scientists disagree by quite a bit  -  up to 4 billion years  -  for certain rocks.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[Mars itself isn't much older than 4 billion years.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[So the question is: Do these rocks tell the beginning, or the end, of Mars' story?Recently, an international team of scientists sought to sort this out for a particular group of meteorites known as shergottites.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[Martian space rocks tend to be very old, but shergottites are generally thought to be remarkably young.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[Most scientists believe they were formed as a result of volcanic activity about 150 to 250 million years ago.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[This would mean they formed during Earth's Jurassic period, when dinosaurs roamed the land.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[If so, shergottites are a sign that Mars might have been geologically active fairly recently.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[That in turn means it might still have been friendly to some form of life, said planetary geochemist Munir Humayun.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[But some scientists have estimated that shergottites are actually about 4 billion years old.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[If this were true, scientists would have to change the way they think about Mars' history.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA["Most of us understand that if there is ... life on Mars, it's not going to be roaming on the surface. ... but it could be thriving underground with the heat energy provided by [volcanoes]," Humayun said.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[However, "if there hasn't been [volcanic activity in] 4 billion years, ... it would be very difficult to believe there was life left on Mars."]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[To settle the question, researchers examined a meteorite known as Northwest Africa 5298.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[They looked at very tiny deposits within it called baddeleyites.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[These tough, zirconium-rich minerals are "10 times smaller than the diameter of a human hair," said geochemist Axel Schmitt.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[Researchers generally measure certain radioactive elements in rocks to figure out how long a rock has been around.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[But when the meteorites slam into Earth, that melts the rock down and can erase the evidence.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[That's why scientists picked the tiny baddeleyites: Once they form, they are durable little minerals.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[It's not easy to melt them down.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[By looking at the radioactive uranium and lead in this tough rock, the scientists found that it formed sometime around 187 million years ago.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[This proved that the baddeleyites were young.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[The scientists could also see evidence of the damage done to the meteorite by whatever event sent it shooting off the Martian surface around 22 million years ago.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[The shock had muddled up the mineral structure inside, though the chemicals themselves were mostly unchanged.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[The result was something like shaking up a sealed gift box of chocolates.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA["It looks good on the outside, but all the pieces are dislodged on the inside," Schmitt said.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[The study further shows that the shergottites weren't old rocks, Humayun said.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[But that was what he had expected.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA["If they had found that it was 4 billion years old, I would eat my hat."]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[The researchers say they can use their method of dating these rocks to study other Martian meteorites.]]></answer>
		<answer isaudiomp3="1" picture="images/c1.jpg" mp3="AUDIO_REPOS/2060-1" isrationalemp3="1" rationalemp3="AUDIO_REPOS/right.mp3" rationaleimage="images/rationale/1.1.jpg" rationale="Right" value="1" choicesay=""><![CDATA[Their hope is that they will discover new information about our neighbor, the Red Planet.]]></answer>
		
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