Scientists reported that the human brain is _____13_____ prepared to assist others, including strangers, and that this _____14_____ behavior can be observed in as young as 18-month-old children. Moreover, the latest discovery of mirror neurons in humans _____15_____ the scientists believe that the human brain can affect a person’s helpful behavior. Mirror neurons located throughout the brain can help us feel what others feel and thus make us feel _____16_____. Without them, we would not know or care about other people’s feelings.

   Today, when we want new clothes, we can go to a clothing store and buy whatever you like. But for people two or three hundred years ago, getting new clothes was not so easy. Not only did they make their own clothing, but sometimes people wove their own cloth at home. And if they owed their own sheep, they even spun the wool into yarn themselves. 

    Wool cannot just be taken from the sheep and spun. First, it must be cleaned and then carded. In a large family, carding was usually the children’s job, because it is easy but tiresome. Carding is done with two wide combs that have rows of steel teeth. The person carding puts a piece of wool on one comb, then pulls the other comb across the wool again and again. This combing makes the wool fibers straight and smooth so they can be spun. 

   Finally, the mother or older sister of the family could use the wool for spinning. Spinning just means twisting and stretching the fibers into yarn. You have spun yarn if you have ever pulled and twisted a cotton ball into a long string. Usually, though, a spinning wheel helps make the pulling and twisting easier. The spinner holds the wool in her hands and twists one end unto the yarn already on the spindle, or long winding stick. The spinning wheel turns the spindle, pulling the wool into yarn and winding it onto the spindle at the same time. Finally, the yarn is ready for weaving. 

   Today, machines can spin yarn much faster than people can. But in some places, people still make their own yarn because they love the old art of spinning.

    A hundred years ago, the largest city in the world was London, with a population of 6.5 million. Today it is dwarfed by Tokyo. With barely a quarter the population of London a century ago, the Tokyo metropolitan area has since mushroomed to 35 million, propelling it to first place in the global city league table. Tokyo’s phenomenal growth is largely due to a single factor: migration from the countryside to the city. It is just one of many to have overtaken London, which with a population of 7.5 million today doesn’t even make the top 20. 

   The rural-to-urban migration can now be seen in scores of cities around the globe. And it has brought us to a pivotal moment in human history. In 1900, most people lived in the countryside, with a little over 10 percent of the world’s population living in cities. From next year, the UN Population Division predicts that for the first time in history, more people will live in cities than in the country, and the biggest growth will be in “megacities,” with 10 million.

   The meteoric growth of megacities—there are now more than 25 in total—has brought with it huge environmental and social problems. Cities occupy just two percent of the land surface of the Earth but consume three-quarters of the resources that are used up each year, expelling greenhouse gases, billions of tons of solid waste, and rivers of toxic sewage. Their inhabitants are making ruinous demands on soils and water supplies for food and on forests for timber and paper.

    Returning the world’s population to the countryside is not an option. Dividing up the planet into plots of land on which we could all survive self-sufficiently would create its own natural disasters, not to mention being highly unlikely to even happen. If we were to protect what is left of nature, and meet the demand to improve the quality of living for the world’s developing nations, finding a new form of city living seems to be the only solution by mobilizing collaborative efforts to address this urgent agenda.

    Barter is an ancient way of commerce: people exchange goods or services directly without using a medium of exchange such, as currency. Usually, the things exchanged or traded have almost the same value in terms of money. Barter is most useful when two people each have something that the other wants. That being the case, they decide on the items to be exchanged and then make the trade. This is also true of services. For example, a plumber can fix a tap in a grocery store and get a few daily necessities in return as payment. 

    Now, this old method of conducting business has taken a new form. In the old days, barters usually took place between two parties. Over time, organized barter exchanges have developed, which means we now have third-party bartering. A barter exchange serves as a broker and also as a banlc in which each member has an account. When a purchase is made, “trade dollars” are taken away from the buyer’s account and added to the seller’s account. Of course, this can be done electronically now. There are online barter networks available that make it much easier to trade with many businesses. 

    Bartering tends to become more popular in times of struggling economies. Since trade dollars are used, this form of exchange appeals especially to businesses that are short of cash. Also, it helps get rid of excess goods or services, that is, those that aren’t sold. If, say, a restaurant needs to have its carpet cleaned, it can provide catering service in its opening yet free hours for a carpet cleaner that needs a feast. What’s more, it can draw in many new customers through this expanding network. Next time, when you find yourself in need of something, don’t buy but try bartering!