Cambridge ielts 1-15 series reading answers explained

CAMBRIDGE IELTS 7 – TEST 3 – PASSAGE 1
ANT INTELLIGENCE 

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123 
POPULATION MOVEMENTS AND GENETICS 
QUESTIONS 14-19 CHOOSE THE CORRECT HEADING 
14. SECTION A 
This is a short paragraph. Skimming through the whole paragraph, it can be seen that the writer talks 
about the development in techniques of studying population movements by using words indicating 
development: used to be based on – developed-the best -now being obtained… The writer also refers 
to early population movements in this section: “Study of the origins and distribution of human 
population used to be based on…. A number of new techniques developed…. the best information on 
early population movements is now being…” Looking back at the heading list, it can be seen that 
heading – iv. Developments in the methods used to study early population movements – deals with 
early population movements and its content matches the main content of the section 
+ methods = techniques 
=> ANSWER: iv Developments in the methods used to study early population movements 
15. SECTION B 
From the first sentence, we can infer that the paragraph is going to deal with migration to America: 
“Recent work on the problem of when people first entered the Americas is an example of the value of 
these new techniques.” Then the author continues with 2 questions “But was there one major wave of 
migration?….And when did this event, or events, take place?” Looking back at the heading lists, the 
most suitable heading should be vii. Long-standing questions about prehistoric migration to America 
+ prehistoric migration to America corresponds to the problem of when people first entered the 
Americas 
=> ANSWER: vii Long-standing questions about prehistoric migration to America 
16.SECTION C 
In the first sentence , the writer says : ” An important project, led by the biological anthropologist 
Robert Williams, focused on the variants (called Gmallotypes) of one particular protein … found in the 
fluid portion of human blood.” Then in the last sentence he concludes: “Thus, by comparing the 
Gmallotypes … one can establish their genetic “distance”, which can be calibrated to give an 
indication of the length of time since these populations last interbred.” So it can be inferred that the 
paragraph deals with how variants of protein in our blood are used to explore relationships among 
different populations. 
The most suitable heading is x. How analysis of blood-variants measures the closeness of the 
relationship between different populations 
+ blood-variants = the variants found in human blood 
+ measure corresponds to „give an indication of the length of…‟ 

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+ closeness of the relationship corresponds to genetic distance, interbred 
=> ANSWER: x How analysis of blood-
variants measures the closeness of the relationship between different populations 
17. SECTION D 
In the first sentences, the writer reports: ” Williams and his colleagues sampled the blood of over 
5000 American Indians….They found that their Gmallotypes could be divided into two groups… 
Other tests showed that. …From this evidence, it was deduced that…” So we know that the paragraph 
refers to the result of Williams‟s project – the tests carried out and the evidence found from the results. 
The best suitable heading is: 
=> ANSWER: i The result of the research into blood-variants 
18. SECTION E 
In the first sentence, the writer poses a question : ” How far does other research support these 
conclusions?” followed by the next sentence: ” Geneticist Douglas…” So, it is clear that the other 
research is carried out by this geneticist – it is genetic research. The conclusions which this genetic 
research supports is the conclusion mentioned in Section D – that there were three waves of 
migration. So the most suitable heading is: 
=> ANSWER: vi:Further genetic evidence relating to the three-wave theory. 
19. SECTION F 
In the first sentence, the writer says : ” There are two other kinds of research… they involve the study 
of teeth and languages.” Then he continues: “The biological anthropologist Christy Turner is an expert 
in…human teeth.” After that,by skimming, it can be seen that the other part of the paragraph consists 
of words relating to “teeth” : crown, root, incisor. Therefore, we know that the paragraph is about 
evidence in terms of teeth. The most suitable heading is ii. Dental evidence 
+ dental = relating to teeth 
=> ANSWER: ii Dental evidence 
QUESTIONS 20-21 
20. INFORMATION ABOUT WILLIAMS‟S RESEARCH IS IN SECTION D. 
The writer states: ” From this evidence it was deduced that there had been three major waves of 
migration across the Bering Strait. The first, Paleo-Indian, wave more than 1500 years ago was 
ancestral to all Central and South American Indians.” 
Only route E goes from somewhere in Asia, across the Bering Strait and then continues to Central and 
South America 
=> ANSWER: E 
21. IN THE NEXT SENTENCE, THE WRITER SAYS: ” THE SECOND 
WAVE…(WHO ONLY MIGRATED SOUTH FROM CANADA ABOUT 600 
OR 700 YEARS AGO.” 
The map shows this second wave took place over two periods, indicated by the dotted line (C) – the 
first period 14,000 to 12,000 years ago. After a long time in Canada, in the second period 600 or 700 
years ago, these people migrated south from Canada to the USA, shown on the map by the arrows, 
D. So, this route is from Canada to the USA, 600 or 700 years ago. 
=> ANSWER: D 

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125 
QUESTIONS 22-25 
22. AGAIN, IT IS SECTION D WHICH FIRST REFERS TO THE , THREE 
WAVE THEORY. 
The writer states :”The third wave, perhaps 10,000 or 9,000 years ago, saw the migration from North 
East Asia of groups ancestral to the modern Eskimo (Inuit) and Aleut”. 
=> ANSWER: C 
23. IN THE SAME PARAGRAPH, THE WRITER ALSO SAYS : 
” The second wave…brought Na-Dene hunters, ancestors of the Navajo and Apache …” 
=> ANSWER: B 
24. PIMA-PAPAGO 
In Section E, the writer states: ” Geneticist Douglas Wallace has studied….Pima-Papago 
Indians…Maya Indians and Ticuna Indians……all three groups appear to be descended from the same 
ancestral (Paleo -Indian) population. ” We know from Section D, that this population was the first 
wave: ” The first, Paleo-Indian, wave…” 
=> ANSWER: A 
25. TICUNA 
=> ANSWER: A 
QUESTION 26. CHOOSE THE CORRECT LETTER A, B, C, D CHIRSTY 
TURNER‟S RESEARCH INVOLVED THE EXAMINATION OF 
Keywords : Christy Turner‟s research, examination 
Christy Turner‟s research is described in Section F:We know that: “Christy Turner is an expert in the 
analysis of changing physical characteristics in human teeth.”Studies carried out by Turner of many 
thousands of New and Old World specimens, both ancient and modern, suggest that the majority of 
prehistoric Americans are linked to Northern Asian populations by crown and root traits and …” So, 
Turner‟s research examined thousands of New and Old World teeth, both ancient and modern. 
=> ANSWER: A. teeth from both prehistoric and modern Americans and Asians 
+ teeth is specimens 
+ prehistoric = ancient 
+ New World = American 
+ Old World = Europe, Asia and Africa 
B, D are not correct because the object of the study is specimens of teeth, not humans or eating 
habits. C is not correct because specimens were studied not only from prehistoric Americans, but also 
modern Americans, as well as ancient and modern Asians.