We study history by Era because?

Which of the following is not true of television journalism? television is even more effective than the radio as an agency for influencing public opinion. you must pay millions of dollars to build up and project the proper television image for their candidates. television media performs a public service in the field of political education. we should form our opinions by listening to network commentators to get a well-rounded perspective, as you can assemble from different sources we should listen to more than one commentator and read background articles in boo and magazines

John locke viewed the social contract as a choice or "consent of the governed", where the people possess the power to change government. how did thomas hobbes see the social contract? man is born in chains, but can be set free through good deeds. man is born happy, but becomes more miserable as he ages. man is born poor, but can rely on other individuals for security. man is born selfish, but can give up some freedom in return for security provided by the government.

What were two theories put forth by marx?