A、The common features of both insect and human societies. B、The differences between insect society and human society. C、The role

A common feature of both insect and human societies is that they consist of individuals living together and behaving as a group. They also resemble each other in that in each society different individuals have different jobs to do. The basic unit of each society is the family, (26) but there is an important difference: with insects the family is the society; with humans, on the other hand, the society consists of a group of families or a group of individuals from different families.
    (26) We have noted that in both societies different individuals perform different functions or roles. Among insects the number of roles is very small. In a termite society, for example, there are four basic roles: the queen, the king, the workers and soldiers. (27) In modern human society, in contrast, there are thousands of different occupations. Furthermore, (28) in human society an individual has a choice of roles, whereas in insect society there is no choice. A queen is born a queen and a worker is born a worker. Nor can an insect change roles. A queen cannot decide to stop laying eggs and become a worker instead. With humans, the opposite is the case, because (29) human roles are always learned whereas insects can only perform the role they were born to do.
    Finally, although there are other distinguishing features, it is important to note that an insect has almost no chance of staying alive if it goes away from its group. A human individual, however, can not only survive outside his own group, but also change from one group to another. He may be happiest if separated from it, or he can change it for another.
Questions:26. What is the main point of the passage?
27.What is the main similarity between insect society and human society?
28.What is the difference between insects and human beings in terms of roles?
29.Why can human roles be changed?