It is hard to box against a southpaw, as Apollo Creed found out when he fought Rocky Balboa in the first of an interminable series of movies. While "Rocky" is fiction, the strategic advantage of being left-handed in a fight is very real, simply because most right-handed people have little experience of fighting left-handers, but not vice versa. And the same competitive advantage is enjoyed by left-handers in other sports, such as tennis and cricket.The orthodox view of human handedness is that it is connected to the bilateral specialization of the brain that has concentrated language-processing functions on the left side of that organ. Because, long ago in the evolutionary past, an ancestor of humans ( and all other vertebrate animals ) underwent a contortion that twisted its head around 180~ relative to its body, the left side of the brain controls the right side of the body, and vice versa. In humans, the left brain (and thus the right body) is usually dominant. And on average, lefthanders are smaller and lighter than right-handers. That should put them at an evolutionary disadvantage. Sporting advantage notwithstanding, therefore, the existence of left-handedness poses a problem for biologists. But Charlotte Faurie and Michel Raymond, of the University of Montpellier Ⅱ , in France, think they know the answer. As they report in the Proceedings of the Royal Society, there is a clue in the advantage seen in boxing.As any schoolboy could tell you, winning fights enhances your status. If, in prehistory, this translated into increased reproductive success, it might have been enough to maintain a certain proportion of left-handers in the population, by balancing the costs of being left-handed with the advantages gained in fighting. If that is true, then there will be a higher proportion of left-handers in societies with higher levels of violence, since the advantages of being left-handed will be enhanced in such societies. Dr Faurie and Dr Raymond set out to test this hypothesis.Fighting in modem societies often involves the use of technology, notably firearms, that is unlikely to give any advantage to left-handers. So Dr Faurie and Dr Raymond decided to confine their investigation to the proportion of left-handers and the level of violence ( by number of homicides) in traditional societies.By trawling the literature, checking with police departments, and even going out into the field and asking people, the two researchers found that the proportion of left-handers in a traditional society is, indeed, correlated with its homicide rate. One of the highest proportions of left-handers, for example, was found among the Yanomamo of South America. Raiding and warfare are central to Yanomamo culture. The murder rate is 4 per 1 000 inhabitants per year (compared with, for example, 0.068 in New York). And, according to Dr Faurie and Dr Raymond, 22.6% of Yanomamo are left-handed. In contrast, Dioula-speaking people of Burkina Faso in West Africa are virtual pacifists. There are only 0. 013 murders per 1 000 inhabitants among them and only 3.4% of the population is left-handed.While there is no suggestion that left-handed people are more violent than the right-handed, it looks as though they are more successfully violent. Perhaps that helps to explain the double meaning of the word "sinister". The two doctors might support which of the following statements()
A. Left-handers stand a better chance of winning than right-handers in violence.
B. Left-handers are more likely to commit crimes than the right-handers.
C. Left-handers are directly responsible for the violence in traditional societies.
D. There is no evidence that left-handers are more violent than right-handers.
Few insects have inspired as much fear and hatred as the diminutive fire ants, less than half an inch long but living in colonies of more than 250,000 others. Everyone in the southern United States gets to know fire ants sooner or later by painful experience. Fire ants live in large earthen mounds and are true social insects--that means they have a caste system ( division of labor), with a specialized caste that lays eggs (queen) and a worker caste of sterile females. There are several reasons that they are considered pests. About 60% of people living in areas where fire ants occur are stung every year. Of these, about 1% have some degree of allergic reaction ( called anaphylaxis) to the sting. Their large mounds are unsightly and can damage mowing equipment. Fire ants sometimes enter electrical and mechanical equipment and can short out switches or chew through insulation. Finally. as fire ants move into new areas, they reduce diversity of native ants and prey on larger animals such as ground-nesting birds and turtles.Even though fire ants are pests in many circumstances, they can actually be beneficial in others. There is evidence that their predatory activities can reduce the numbers of some other important pests. In cotton, for example, they prey on important pests that eat cotton plants such as bollworms and budworms. In Louisiana sugarcane, an insect called the sugarcane borer used to be a very important pest before fire ants arrived and began preying on it. Fire ants also prey on ticks and fleas.Whether fire ants are considered pest or not depend on where they are found, but one thing is sure—we had best get used to living with them. Eradication attempts in the 1960s and 1970s failed for a number of reasons, and scientists generally agree that complete elimination of fire ants from the United States is not possible. A new, long-term approach to reducing fire ant populations Involves classical biological control. When fire ants were accidentally brought to the United States, most of their parasites and diseases were not. Classical biological control involves identifying parasites and diseases specific to fire ants in South America, testing them to be sure that they don ’ t attack or infect native plants or animals and establishing them in the Introduced fire ant population In the United States. Since fire ants are about 5 to 7 times more abundant here than in South America, scientists hope to reduce their numbers using this approach. That fire ants prey on bollworms and budworms is mentioned to show that()
A. pests often attack each other to maintain a balance of nature.
B. fire ants are not always harmful pests in given situations.
C. fire ants are stronger and fiercer than bollworms and budworms.
D. pests are either harmful or beneficial to people or plants.