In each pair, click on the better introduction, the one that, in addition to engaging the reader's attention, clearly states a thesis

1.

A. The Consumer Product Safety Commission recommends safety standards for children's toys and playground equipment. The commission suggests hard rubber surfaces under play areas in public spaces and in backyards. Dangling ropes can be dangerous, and children can also hurt themselves on swings that are too high or that can get tangled up with other equipment nearby. Naturally, young children should be supervised in any play area.
B. The Consumer Product Safety Commission, which recommends safety standards for children's playground equipment, seems bent on preventing children from getting the slightest bump, bruise, or scrape. Of course children need safe places to play, but the occasional splinter or skinned knee is part of normal childhood. When the commission makes installing a jungle gym or merry-go-round needlessly difficult and expensive, fewer playgrounds are built, especially in poor communities. The commission should adopt a more realistic approach to playground safety, one that protects children but does not make the cost of building play areas prohibitively expensive.
2

A. Every election year, political parties and candidates raise millions of dollars in soft money, contributions that sidestep laws limiting the amount of money a candidate can receive from any one source. Because unregulated soft money can make winning candidates feel indebted to wealthy donors such as unions and corporations, Congress must close the undemocratic loopholes in current campaign finance laws.
B. Soft money is the term used for campaign contributions that sidestep laws governing the amount of contributions candidates can receive from any one source. Many election campaigns are financed largely with soft money, whether it is raised by the candidates themselves or by their party organizations. Soft money pays for items such as television ads that endorse a political issue rather than a candidate.

3.
A. In the eighteenth century, an English clockmaker named John Harrison received a prize for a clever invention that allowed sailors to calculate longitude. He created a clock that required no pendulum and contained different kinds of metal. This clock worked on board a ship that was at sea, and it worked in many different temperatures and climates.
B. Until the eighteenth century, sailors at sea had no way of calculating the longitude of their ships with any accuracy. As a result, countless sailors died when they lost track of their position and their ships ran aground. Great scientific minds tried to solve the problem of longitude without success, but it was a self-taught English clockmaker, John Harrison, who invented a device that worked. Harrison's invention must rank as one of the greatest contributions to the field of navigation.

4.

A. After school let out for the summer in early June, I went straight to a local fast-food restaurant and filled out an application. The manager called a few days later and asked me to come in for an interview. Although one of my friends told me the work there was hot and boring and the pay was not good, I took the position anyway when the manager offered it to me. I didn't like the job much in the beginning, but by the end of the summer I was glad to have had the experience.
B. A summer job at a burger joint taught me lessons I might not otherwise have learned for years. I discovered that many people treat workers in menial jobs with contempt, and I learned how miserable it feels to be treated that way. Working with people I had always despised in high school taught me that I had judged others too quickly. Finally, I learned to question bad decisions made by my supervisors%u2014even though I ended up unemployed as a result. Though burger flipping paid only the minimum wage, it taught me valuable lessons about life.

5.
A. The reintroduction of wolves into YellowstoneNational Park restores an important missing piece to the ecosystem. Wolves, hunted to extinction in Wyoming and Montana in the twentieth century, occupy a vital place in the natural cycle of the area. As predators, wolves control the population of deer and other herbivores, which otherwise reproduce prolifically. Returning the wolves to the place where they once belonged will eventually reestablish the natural balance in this wild and beautiful part of the United States.
B. Because every part of an ecosystem affects every other part, disturbing the natural cycle can have devastating effects. In almost every type of environment, a variety of plants feed a variety of small herbivores, which in turn feed a variety of predators. Wolves are a good example of predators that should not be disturbed.