Over a period of time, many habitats change with respect to the types of plants and animals that live there. This change is known as succession. Succession occurs because plants and animals cause a change in the environment in which they live. The first weeds and grasses that appear on a bare field, for example, change the environment by shielding the soil from direct sunlight. As these plants spread, the ground becomes cooler and more moist than it was originally. Thus, the environment at the ground surface has been changed. The new surface conditions favor the sprouting of shrubs. As shrubs grow, they kill the grasses by preventing light from reaching them and also enhance the soil. Pine seedlings soon take hold and as they grow, they in turn shade out the shrubs. They are not able to shade out oak and hickory seedlings, however, that have found the forest floor suitable. These seedlings grew into large trees that eventually shade out the pines. It can be inferred from the passage that _ . A) oak and hickory trees grow taller than pines B) weeds and grasses prefer cold climate C) pines and grasses can exist together D) birds encourage the growth of shrubs
A
Still seeking a destination for your weekend break? There are some places which are probably a mere walk away from your college. King's Art Centre A day at the Centre could mean a visit to an exhibition of the work of one of the most interesting contemporary artists on show anywhere. This weekend tees the opening of an exhibition of four local artists. You could attend a class teaching you how to 'learn from the masters' or get more creative with paint ---- free of charge. The Centre also runs two life drawing classes for which there is a small fee. The Botanic Garden The Garden has over 8,000 plant species; it holds the research and teaching collection of living plants for Cambridge University. The multi-branchedTorch Aloe here is impressive. The African plant produces red flowers above blue-green leaves, and is not one to miss. Get to the display house to seeDionaea muscipula, a plant more commonly known as the Venus Flytrap that feeds on insects and other small animals. The Garden is also a place for wildlife-enthusiasts. Look for grass snakes in the lake. A snake called 'Hissing Sid' is regularly seen lying in the heat of the warm sun. Byron's Pool Many stories surround Lord Byron's time as a student of Cambridge University, Arriving in 1805, he wrote a letter complaining that it was a place of "mess and drunkenness". However, it seems as though Byron did manage to pass the time pleasantly enough. I'm not just talking about the pet bear he kept in his roans. He spent a great deal of time walking in the village. It is also said that on occasion Byron swam naked by moonlight in the lake, which is now known as Byron's Pool. A couple of miles past Grantchester in the south Cambridgeshire countryside, the pool is surrounded by beautiful circular paths around the fields. The cries of invisible birds make the trip a lovely experience and on the way home you can drop into the village for afternoon tea. If you don't trust me, then perhaps you'll take it from Virginia Woolf- ----over a century after Byron, she... We can infer from the passage that Byron seemed _ . A) to fear pet bears B) to like walking C) to be a heavy drinker D) to finish university in 1805
B
Q: During the outbreak of 2009-2010 H1N1 or "swine flu", the same virus that caused mild coughing and sneezing in some patients proved deadly for others. It highlighted a medical mystery: why are some people more fit to handle the flu than others? British and American researchers think they have a clue. Reporting on Sunday in the journal Nature, researchers say they've found a gene that influences our ability to fight against flu illness. The gene, called IFITM3, is the "important first line of defense" against the flu, researcher Paul Kellam of Britain's Sanger Institute told Reuters. The IFITM3 protein prevents flu viruses from reproducing in cells. So, if you have a high amount of IFITM3, you're in luck, since it weakens the spread of the virus; a low amount can lead to more rapid viral reproduction, causing severe flu symptoms, according to Kellam. Scientists first found in gene studies that IFITM3 played a role in resistance to flu and other viruses. In experiments in mice, they showed that when mice were raised to lack the IFITM3 gene and then infected with influenza, the animals developed more severe lung infection from flu, compared with mice that had the gene. To figure out the role of IFTTM3 in humans, researchers then studied the IFITM3 genes of 53 patients with the flu in 2009-2010. They found that these patients were more likely to have a variant of the IFITM3 gene -- which makes people more vulnerable to flu -- compared with the general population. According to evidence from large genetic databases, about 1 in 400 people carries this IFITM3 variant, the BBC reports. "Our research is important for people who have this variant as we predict their immune defenses could be weakened to some virus infections," said Kellam. The Findings also suggest that a drug that functions as IFITM3 could help increase resistance to flu and other viruses, including deadly ones like H5N1 flu. Which of the following can serve as the best title of the passage? A) Why Flu Hits Some People Harder B) How We Protect Ourselves From Flu C) How We Get Infected With Flu D) Why Flu Breaks Out Among People
A: A
When couples get married, they usually plan to have children. Sometimes, however, a couple can not have a child of their own. In this case, they may decide to adopt a child. In fact, adoption is very common today. There are about 60 thousand adoptions each year in the United States alone. Some people prefer to adopt _ , others adopt older children, some couples adopt children from their own countries, and others adopt children from foreign countries. In any case, they all adopt children for the same reason ---- they care about children and want to give their adopted child a happy life. Most adopted children know that they are adopted. Psychologists and child-care experts generally think this is a good idea. However, many adopted children or adoptees have very little information about their biological parents. As a matter of fact, it is often very difficult for adoptees to find out about their birth parents because the birth records of most adoptees are usually sealed. The information is secret so no one can see it. Naturally, adopted children have different feelings about their birth parents. Many adoptees want to search for them, but others do not. The decision to search for birth parents is a difficult one to make. Most adoptees have mixed feelings about finding their biological parents. Even though adoptees do not know about their natural parents, they do know that their adopted parents want them, love them and will care for them. According to the passage, some couples adopt children because _ A) They care a lot about children. B) They need looking after in their old age. C) They want to enrich their life experience. D) They want children to keep them company.
A