TRÍ ĐỨC ENGLISH - IELTS READING MASTERY

[Paragraph A] In recent experiments, neuroscientists at University College London (UCL) asked 15 volunteers to view specific pictures at the same time they were exposed to unrelated odours. For instance, the subjects might see a photo of a duck paired with the scent of a rose, and then be asked to create a story linking the picture with the odour. Brain scans taken at the time revealed that the volunteers' brains were particularly active in a region known as the olfactory cortex, which is known to be involved in processing smells.

[Paragraph B] A few minutes later, the volunteers were shown the same photo with no exposure to the rose smell. And in their brains, the olfactory cortex lit up again, even in the absence of the rose scent. The fact that this happened gives evidence to the idea that people's sensory memory is distributed and retained by multiple regions of the brain. "Imagine going on a seaside holiday," says UCL team leader, Jay Gottfried. "The sight of the waves becomes stored in one area, whereas the crash of the surf goes elsewhere, and the smell of seaweed in yet another place. There could be advantages of having memories spread around the brain."

[Paragraph C] Both Darwin and Wallace had realized that the anomalous distribution of species in particular regions had profound evolutionary significance. As a result of his correspondence with Wallace and his conversations with Lyell and Hooker, Darwin opted to sequester himself in near seclusion, where he spent his remaining days studying and writing about the origin of the species. Wallace, on the other hand, applied himself to the science of biogeography, the study of the pattern and distribution of species, and its significance.

[Paragraph D] Scientists speculate that the lack of magnetic shield helped the solar wind blow away much of Mars's atmosphere over the course of several billion years. After mapping cosmic radiation levels at various depths on Mars, researchers concluded that any life within the first several meters of the planet's surface would have been killed by lethal doses of cosmic radiation. In 2007, it was calculated that DNA and RNA damage by cosmic radiation would limit life on Mars to depths greater than 7.5 metres below the planet's surface. Therefore, the best chance of discovering life on Mars may be in subsurface environments that have not yet been studied.

[Paragraph E] Did Mars hold liquid water in surface lakes or oceans years ago? Liquid water is necessary for all the metabolic processes of life on Earth, so any evidence of water on Mars would indicate the existence of life. Certainly, it is an inhospitable place now, with its low atmospheric pressure, low temperature, and aridity. However, the Mars Express orbiter did detect huge reserves of ice at the planet's south pole in January 2004, and two months later NASA announced that its rover Opportunity had discovered evidence that Mars was, in the ancient past, a wet planet.