The Maya were an ancient people who lived in what is now Central America that have some 3,000 years of rich history. The Maya excelled at agriculture, pottery, hieroglyph writing, calendar-making and mathematics, and left behind an astonishing amount of impressive architecture and symbolic artwork. All Maya shared a common culture and religion, but each city governed itself and had its own noble ruler. These cities never came together to form a single empire since the kings were constantly at war with each other. This constant fighting could have led to their decline. In the 8th and 9th centuries AD, Classic Maya culture went into decline, with most of the cities of the central lowlands abandoned. Warfare, ecological depletion of croplands, and drought or some combination of those factors are usually suggested as reasons for the decline. What is the central idea of this passage?

The Tour de France is probably the worlds most famous cycle race. It takes place over 23 days and covers over 2,000 miles. Each year the race takes a different route, but ever since 1975 the finish has always been in Paris with a magnificent sprint down the Champs-Élysées. At the end of each day's race, the leader is given a yellow shirt, the best sprinter is given a green shirt, and the best rider in the mountain races is given a polka dot jersey. He is sometimes called the King of the Mountains. The best young rider, who must be under 25, gets a white jersey. The winner is the one who finishes the race to Paris in the fastest time. There is a lot of prize money for the teams of the winners of the Tour, but the winner of each day's race also gets prize money. What is the central idea of the passage?

Reality television is touted a genre of television programming which presents unscripted dramatic or humorous situations, document actual events, and have ordinary people instead of professional actors. However, critics argue that reality television shows do not accurately reflect reality since participants are placed in artificial situations and given scripts or story lines to follow. Other critics say reality TV make stars out of untalented people unworthy of fame. Many people still tune into their favorite reality TV show since it is fun to watch, but they take it with a grain of salt and put it in the same category as scripted sitcoms. What is the central idea of this passage?

We all know that every snowflake is unique and we assume a scientist discovered this fact. Surprisingly it was not a scientist, but a young farmer from Vermont, who took the first micro-photograph of a snowflake in 1885 when he just 19 years old. Wilson Bentley always loved nature so when he received a microscope for his 15th birthday, the first thing he did was try and examine a snow flake. Intrigued by their unusual designs, he tried to sketch detailed drawings, but the snow would melt before he could get it done. He decided it would be better to photograph them. This was not an easy process, and it took him 2 years to figure out. But once he got started he could not stop. Bentley went on to capture over 5,000 images, and was the first one to realize that no two snow flakes were alike. What is the central idea of this passage?

In 1890 the first hairdryer was invented by French stylist Alexander Godefroy. His invention was a large, seated version that consisted of a bonnet that attached to the chimney pipe of a gas stove. Godefroy invented it for use in his hair salon in France, and it was not portable or handheld. It could only be used by having the person sit underneath it. This invention led to the first patent of a portable hair dryer in 1911, and handheld dryers finally arrived in homes around 1920. Hard to believe that before hair dryers could be mass produced at affordable prices, women would sit next to a stove or fireplace and some resorted to using hose attachments at the exhaust end of a vacuum cleaner to dry their hair! Hairdryers have come a long way over the years. What is the central idea of the passage?

For most American kids, it wouldn’t be Halloween without trick-or-treating for candy. However, when trick-or-treating first started candy wasn't even an option. In the 1930s and early 1940s, children were given everything from homemade cookies and pieces of cake to fruit, nuts, coins and toys. It wasn't until the 1950s when candy manufacturers began to get in on the act and promote their products for Halloween. As trick-or-treating became more popular, candy was considered an affordable, convenient offering. It wasn’t until the 1970s, though, that wrapped, factory-made candy was viewed as the only acceptable thing to hand out to all the little ghosts and goblins that showed up on people’s doorsteps. What is the central idea of the article?