Which groups of people deny that the holocaust happened?

The Holocaust denial was supported by some middle eastern governments, such as Iran and Syria.

Explanation:

worldwide, 780 million people do not have access to an improved water source. an estimated 2.5 billion people lack access to improved sanitation (more than 35% of the world's population)

a social contract.

"a social contract is an agreement between citizens and their leader where the citizens give up certain freedoms in exchange for protection. the constitution of the united states is an example of a social contract."