*Question*
Read the article and select the best answer. Article: Can people change their skin color1 without suffering like pop king Michael Jackson? Perhaps yes. Scientists have found the gene that determines skin color1. The gene comes in two versions, one of which is found in 99 percent of Europeans. The other is found in 93 to 100 percent of Africans, researchers at Pennsylvania State University report in the latest issue of science. Scientists have changed the color1 of a dark-striped zebrafish to uniform gold by inserting a version of the pigment gene into a young fish. As with humans, zebrafish skin color1 is determined by pigment cells, which contain melanin . The number, size and darkness of melanin per pigment cell determine skin color1. It appears that, like the golden zebrafish, light-skinned Europeans also have a mutation in the gene for melanin production. This results in less pigmented skin. However, Keith Cheng, leader of the research team, points out that the mutation is different in human and zebrafish genes. Humans acquired dark skin in Africa about 1.5 million years ago to protect bodies from ultra-violet rays of the sun , which can cause skin cancer. But when modern humans leave Africa to live in northern latitudes, they need more sunlight on their skin to produce vitamin D. So the related gene changes, according to Cheng. "Asians have the same version of the gene as Africans, so they probably acquired their light skin through the action of some other gene that affects skin color1," said Cheng. The new discovery could lead to medical treatments for skin cancer. It also could lead to research into ways to change skin color1 without damaging it like chemical treatment did on Michael Jackson. ks5u Question: The passage mainly tells us that _ . Options: A: people can not change their skin color1 without any pain B: the new discovery could lead to research into ways to change skin color1 safely C: pop king Michael Jackson often changed his skin color1 as he liked D: scientists have found out that people's skin color1 is determined by the gene
**Answer**
D

*Question*
Read the article and select the best answer. Article: Anthropologists are scientists that study people who often lived hundreds or even thousands of years ago. Items those men, women, and children left behind when they died --- everything from clothing to jewelry and tools --- tell anthropologists a lot. And sometimes even their words survive. Experts believe that a discovery in Mexico is the oldest example of writing ever found in the Americas. The people who created it probably lived 3,000 years ago, long before Christopher Columbus arrived in the New World. Workers digging in a rock mine happened to notice a stone block with marks carved onto its surface. They found the large piece of stone near the city of Cascajal, Mexico, which was once the capital of an ancient people called the Ohmec. "There are signs on the block that seem to show objects used by the Olmec during their religious ceremonies," says Dr. Stephen Houston, of Brown University in the USA. "There is a sign that looks very similar to a knife and another that looks like the chair of a King," he explains. Houston, an expert on the writing systems of ancient cultures, says the discovery is exciting because "it makes clear that the Olmec could read and write. It is like hearing voices from the past." But experts don't know exactly what the writing says. Finding other examples of Olmec writing could help decipher the puzzle. "We could have whole sets of ancient writing which will basically make ancient people speak to us directly," says Houston. "There are many puzzles to be solved, and this is just one of them." Question: According to the passage, what items do scientists often use to learn more about the past? Options: A: Clothing and jewelry. B: Books and stones. C: Knives and chairs. D: People and animals.
**Answer**
A

*Question*
Read the article and select the best answer. Article: People with mentally taxing jobs, including lawyers and graphic designers, may end up having better memory in old age, research suggests. A study of more than 1,000 Scottish 70-year-olds found that those who had had complex jobs scored better on memory and thinking tests. One theory is that a more stimulating environment helps build up a "cognitive reserve" to help buffer the brain against age-related decline. The research was reported in Neurology. The team, from Heriot-Watt University, in Edinburgh, is now planning more work to look at how lifestyle and work interact to affect memory loss. Those taking part in the study took tests designed to assess memory, processing speed and general thinking ability, as well as filling in a questionnaire about their working life. The analysis showed that those whose jobs had required complex skills in dealing with data or people, such as management and teaching, had better scores on memory and thinking tests than those who had done less mentally intense jobs such as factory workers, bookbinders, or carpet layers. While the study did not look at biological reasons for the protective effect of certain jobs, potential explanations include that structural changes within the brain mean less damage is accumulated over time. Study leader Dr Alan Gow said: "Our findings have helped to identify the kinds of job demands that preserve memory and thinking later on." "However," He added, "while it is true that people who have higher cognitive abilities are more likely to get more complex jobs, there still seems to be a small advantage gained from these complex jobs for later thinking skills." Dr Simon Ridley, head of research at Alzheimer's Research UK, said the study added to the growing evidence about factors that affected brain health as we aged. "Keeping the brain active throughout life could be helpful and different types of work may play a role. However, it's important to note that this study points to a small and subtle association between occupation and later-life cognition... Question: According to the research, who may have the best memory in old age? Options: A: Taxi drivers. B: Computer programmers. C: Supermarket cashiers. D: Motor mechanics.
**Answer**
B