If the pythons are (5).................. unchecked, there is a strong possibility they will wipe out a variety of species necessary for the functioning of the Everglades ecosystem.

Although the scientific method is now four or five hundred years old, the ancient Greeks, for example, believed that they could (3)_____ the causes of natural events just by the power of thought. During the 17 century, more and more people began to realize that they could test their scientific ideas by designing a relevant experiment
and seeing what happened.

CRITICISM
It can take a long time to become successful in your chosen field, however talented you are. One thing you have to be aware of is that
you will face criticism along the way. The world is full of people who would rather say something negative than positive. If you’ve made up your (1) to achieve a certain goal, such as writing a novel, don’t let the negative criticism of others prevent you from reaching your target, and let the (2) criticism have a positive effect on your work. If someone says you’re totally lacking in talent, ignore them. That’s negative criticism. If, (3) , someone advises you to revise your work and gives you good reasons for doing so, you should (4) their suggestions very carefully. There’re many movie stars who were once out of work. There’re many famous novelists who made a complete trash of their first novel – or who didn’t, but had to put off approaching hundreds of publishers before they could get it published. Being successful does depend on luck, to a (5) . But things are more likely deal with well if you persevere and stay positive.

Scuba diving is a sport in (1) you swim underwater for extended (2) using special equipment. The word Scuba is actually an acronym for
self-contained underwater breathing apparatus. Scuba diving is an excellent way to see some very beautiful sites: coral diving sites with their colorful sea life are the most famous but other scuba diving (3) include shipwrecks and caverns. Scuba diving can also be a very relaxing sport and in many places it’s very beginner friendly. Many dive sites are (4) (under the care of an instructor) after a short briefing and training dive. You can learn to dive far more quickly than you learn snow sports, for example. It’s also suitable for people with a number of physical disabilities. (5) you can use the breathing equipment and are able to successfully propel yourself underwater you may be able to dive.

From all this, the gain to any community no matter how many volunteers are involved is (4)______ .

Polar bears are in danger of dying out. Unlike some other endangered animals, it's not hunters that are the problem, it's climate change. Since 1979, the ice cap at the Arctic Circle where the polar bears live has reduced in size (1)_____ about 30 per cent. The temperature in the Arctic has slowly been rising and this is (2)_____ the sea ice to melt, endangering the polar bears' home. The polar bears' main sources of food are the different types of seals found in the Arctic. They catch them by waiting next to the air holes seals have made in the ice. (3)_____ the bears are very strong swimmers, they could never catch seals in water. This means that the bears really do rely on  the ice to hunt. Polar bears also need sea ice to travel. They can cover a huge territory and often swim from one part of the ice to another. They have been (4)_____ to swim up to 100 km, but when there is less ice, they may have to swim further and this can (5)_____ fatal to the bears. A number of bears have drown in the last few years and scientists believe that it is because they were not able to reach more ice before they became too tired and couldn't swim any further.

Left-handers are the odd ones out. Sure, lefties (1)____ up about 10 percent of the population - but, frankly, it seems like society has forgotten about them. Just consider all of the right-handed gadgets, awkwardly designed desks, and cooking tools that t comfortably only in your right hand. What (2)_____ someone to become a lefthander? Scientists aren’t exactly sure, but research points to a complex (3)_____ between genes and environment. While no exact set of “leftie genes” have been discovered, people who dominantly use their left hands do have more left-handed family members. And researchers have found different brain wirings in righties vs. lefties. But no matter (4)_____ it is that drives someone to use their antipodal paw, science has also uncovered a particular set of personality traits that left-handed people tend to have. So for all of you lefties, leftie-loving righties, and ambidextrous folks out there - it’s time to brush up on your lefthanded knowledge and help (5)_____ an end to leftie discrimination once and for all.

And in the absence of any particular talent, their energy and enthusiasm can be harnessed for the benefit (3) ____ their fellow human beings, and ultimately themselves.

American public education is (5) _______ the responsibility of the states and individual school districts.

In addition to the challenge to be excellent, American schools have been facing novel problems. They must (1)________with an influx of immigrant children, many of whom speak little or no English. They must respond to demands that the curriculum reflect the various cultures of all children. Schools must make sure that students develop (2)________skills for the job market, and they must consider the needs of nontraditional students, such as teenage mothers. Schools are addressing these problems in ways that reflect the diversity of the US educational system. They are opening (3)________the traditional European-centered curriculum to embrace material from American, Asian, and other cultures. Schools are also teaching cognitive skills to the nearly 40 percent of American students who do not go on to higher education. In the (4)________of a recent report by the Commission on Achieving Necessary Skills, “A strong back, the willingness to work, and a high school diploma were once all that was necessary to (5)________a start in America.” Read the reading below carefully, and then complete it with the best option A, B, C or D given below
(1) .............

The unwieldy growth of population leads to the problem of housing and sanitation. In many countries the slums are a (5)_____ to the eyes. Slums grow round big cities and are found with all the drawbacks. These are the areas of disease, filth and crime.
(5) ....................