# Research using twins: answers and explanations

Cambridge IELTS 11, Test 4, Reading Passage 1

Source: Passage, questions and answer key from Cambridge IELTS 11, Test 4, Reading Passage 1. © Cambridge University Press & Assessment. Used for educational practice. Explanations and evidence notes are written by Testmigo.

## Answer key

| Q | Answer | Proof |
| --- | --- | --- |
| 1 | FALSE | Any differences between them - one twin having younger looking skin, for example - must be due to environmental factors |
| 2 | NOT GIVEN | If identical twins are more similar to each other with respect to an ailment than fraternal twins are |
| 3 | NOT GIVEN | Over two decades 137 sets of twins eventually visited Thomas Bouchard's lab |
| 4 | TRUE | Epigenetic processes are chemical reactions tied to neither nature nor nurture |
| 5 | A | (and coined the phrase 'nature and nurture') |
| 6 | C | the latest work in epigenetics promises to take our understanding even further |
| 7 | B | The key to their approach was a statistical concept called heritability. |
| 8 | A | The idea of using twins to measure the influence of heredity dates back to 1875, when the English scientist Francis Galton first suggested the approach |
| 9 | B | the Minnesota Study of Twins Reared Apart |
| 10 | D | Epigenetic processes are chemical reactions ... These reactions influence how our genetic code is expressed |
| 11 | B | to build our bones, brains and all the other parts of our bodies |
| 12 | E | revealing a mechanism by which the environment directly impacts on genes |
| 13 | F | it can cause epigenetic changes in a fetus that lead to behavioral problems as the rodent grows up |

## Why these answers are right

**1. FALSE.** The statement suggests genes may explain why one identical twin's skin looks younger. The first paragraph says identical twins share virtually the same genetic code, so any differences, with younger looking skin as the example, must be due to environmental factors such as sun exposure. That contradicts a genetic cause, so the answer is FALSE.

**2. NOT GIVEN.** This statement compares the disease risk of twins with that of non-twins. The passage only compares identical twins with fraternal twins to see how far an illness is inherited. It never says twins as a group are more likely to get ill than other people, so the answer is NOT GIVEN.

**3. NOT GIVEN.** The statement is about how Bouchard found twins separated at birth. Paragraph D says 137 sets of twins visited his lab over two decades and answered many questions, but it never explains how they were recruited or mentions newspapers. With no information on advertising, the answer is NOT GIVEN.

The why and the trap for questions 4 onwards are free with an account on the [answers page](https://testmigo.com/ielts/reading/research-using-twins/answers).

[Practice Research using twins](https://testmigo.com/ielts/reading/research-using-twins)