Read the following passage and choose the correct answer to each of the questions.

It is hard to get any agreement on the precise meaning of the term “social class”. In everyday life, people tend to have a different approach to those they consider their equals from that which they assume with people they consider higher or lower than themselves in the social scale. The criteria we use to “place” a new acquaintance; however, are a complex mixture of factors. Dress, way of speaking, area of residence in a given city or province, education and manners all play a part.

In Greece, after the sixth-century B.C., there was a growing conflict between the peasants and the landed aristocrats, and a gradual decrease in the power of the aristocracy when a kind of “middle class” of traders and skilled workers grew up. The population of Athens, for example, was divided into three main classes which were politically and legally distinct. About one-third of the total were slaves, who did not count politically at all, a fact often forgotten by those who praise Athens as the nursery of democracy. The next main group consisted of resident foreigners, the “metics”, who were freemen, though they too were allowed no share in political life. The third group was the powerful body of “citizens”, who were themselves divided into sub-classes.

The medieval feudal system, which flourished in Europe from the ninth to the thirteenth century, gave rise to a comparatively simple system based on birth. Under the King, there were two main classes - lords and “vassals”, the latter with many subdivisions.

In the later Middle Ages; however, the development of a money economy and the growth of cities and trade led to the rise of another class, the “burghers” or city merchants and mayors. These were the predecessors of the modern middle class. Gradually high office and occupation assumed importance in determining social position, as it became more and more possible for a person born to one station in life to move to another. This change affected the town more than the country areas, where remnants of feudalism lasted much longer.

The author implies that slaves in Greece in the sixth century B.C. ____.