Every beehive is made up of three kinds of adult bees—workers, drones, and a queen. The jobs of the workers are to tend to all the needs of the queen and all the other bees. They are the bees that gather pollen and nectar for food, clean the hive, construct the honeycomb, tend eggs until they hatch, store the food they gather, feed the queen, and otherwise provide everything else the queen needs. The job of the drones is to mate with the queen to make sure that she will produce more eggs so that the hive will constantly replenish its aging and dying bees. The queen's job is to lay eggs that will produce more bees. If one is concerned purely about the physical portion of the hive and what all the jobs of the bees lead to, the answer would have to be that the driving force of a beehive is the queen because her job is to produce more bees, and, therefore, the workers and drones are present to care for her and to fertilize her eggs.
However, if one takes the answer from the physical level to the conceptual level, the most basic answer would have to be that the force that really unifies and drives a beehive is the concept that all the bees must work together to take care of the queen so that their hive will continue to grow in numbers and prosper in order for their population to divide and produce other colonies, allowing all bee populations to continue to grow and produce. The most basic driving force of all is the need to continue the life of the hive.