1. The Olmec civilization is still surrounded in mystery, and not lot of details are known about it, but it is more of an assumptions by the researchers. The social structure is not well known, but taking in consideration that this civilization influenced pretty much every other later in history in Meso-America, there can be some clues. It is believed that there was ruler with absolute power in the society. The priests were probably ranked second in the hierarchy and they were responsible for the religious practices, keeping the tradition, and teaching. Below it is not certain was there a warrior class as there isn't really any evidence of wars, and the majority of the population was consisted of the people that were engaged in sorts of activities, be it crafting, agriculture, or trade. All of the Olmec cities were well connected, and they all had specialized in something, so they were heavily dependent on each other for goods.
2. The colossal stone heads are the trademark of the Olmecs. These heads are believed to have been made in order to represent their actual rulers, thus they were either symbol of status and power, or they were done to honor the ruler that passed away. All of the heads have different facial features which just strengthens the hypothesis that it is actual people that existed that are depicted. They often have details on them such as helmets or jaguar paws, and the jaguar is thought to have been a sacred animal or even a God, so it probably represents power. These heads can be high as 3 meters and have weight of up to 8 tons. The interesting and confusing thing about these heads is that the faces have typical Australasian facial features, and not facial features that are typically associated with the Native Americans.
3. The Maya empire can be considered as an empire that has build upon the culture of the Olmec civilization. It was not a united empire, but instead there were numerous independent city-states, each of which had its own governing bodies. Unlike the European city-states that were constantly competing and at war with one another, the Mayan ones were in good relations and were collaborating without any problems between them. Even though it was separate city-states, the cultural elements were the same in all of them. The religion was the same, the food consumed was the same, the dressing style, the lifestyle in general, the games, the writing system, the calendar, all were the same, which was definitely because of the constant contact, collaboration, sharing of information and technology between the city-states.