What two countries have the largest economies on earth, accounting for 40 percent of the world's gross domestic product (gdp)?

Why do all market economies have taxes to support armed forces police forces public schools and at least some form of public transportation?

In a study, people were asked to imagine simple occasions that made them happy and to remember events that made them feel proud about themselves. it was observed that the subjects developed an increasingly positive attitude. these changes are known to be healthy, leading to greater physical activity and reducing unhealthy habits. based on this excerpt, we can conclude that a positive attitude .

After 20 minutes of waiting outside the baggage claim area for your friend to pick you up, you decide to go inside the airport terminal and phone her. standing a short distance from you is a kind-looking older woman. "would you mind watching my luggage so i can go make a quick phone call? " you ask politely. "i'd be happy to watch it for you," she replies, "my ride is not coming for another half-hour." when you return less than five minutes later, the old lady and your luggage (including your laptop) are gone. this example illustrates one of the problems associated with: ethnocentrism. the "feel good, do good" effect.the rule of reciprocity. an implicit personality theory.