A

(2023·Ö麣ģÄâ)An individual from an unknown hominid (ԭʼÈËÀà) species walked across a field of wet, volcanic ash in what is now East Africa around 3.66 million years ago, leaving behind a handful of footprints£®

Those five ancient footprints, largely ignored since they were partly unearthed at Tanzania's Laetoli site in 1976, show features of upright walking by a hominid, a new study finds£®Researchers had previously considered them hard to classify, possibly produced by a young bear that took a few steps while standing£®But the latest analysis refutes that suggestion£®

McNutt, DeSilva, who started the new investigation as a Dartmouth College graduate student, and their colleagues fully dug out and cleaned the five Laetoli footprints in June 2019£®Then they measured, photographed and 3­D scanned the ancient tracks£®McNutt's group focused on two footprints that were particularly well­preserved£®Foot shapes, sizes, and walking characteristics of the Laetoli individual differed in various ways from those of other hominid individuals at the same site£®The prints also didn't match those from modern black bears and modern chimps (ºÚÐÉÐÉ) walking upright£®

The Laetoli individual possessed a wider, more chimplike foot than humans, the researchers say£®Its big toe stuck out slightly from the second toe (½ÅÖº), but not to the degree observed in chimps£®On one step, the Laetoli individual's left leg crossed in front of the right leg, leaving a left footprint directly in front of the previous track£®People may cross­step in this way when trying to regain balance£®And bears and chimps assume a relatively wide standing due to knee and other bone arrangements that prevent them from walking like the Laetoli individual and probably from cross­stepping, the scientists say£®

Given that only two of the ancient footprints are complete enough to analyse thoroughly, the possibility that a chimp other than a hominid made the Laetoli footprints can't be ruled out, says William Harcourt Smith, a scientist at Lehman College£®But evidence of cross­stepping is enough to prove that it was a hominid track maker, he says£®

1£®What does the underlined word “refutes”in Paragraph 2 mean?

A£®Objects to£®¡¡¡¡¡¡                  B£®Supports£®

C£®Puts forward£®                      D£®Criticises£®

2£®Why do researchers think the footprints were unlike those of bears or chimps?

A£®They are less chimplike£®

B£®They have toes sticking out£®

C£®They show relatively wide standing£®

D£®They possess features of cross­stepping£®

3£®What does William think of the new research finding?

A£®It's convincing£®

B£®It's challenging£®

C£®It's confusing£®

D£®It's conflicting£®

4£®What is the purpose of the text?

A£®To describe a major event£®

B£®To share a new discovery£®

C£®To introduce an unknown species£®

D£®To settle a huge disagreement£®