What kind of scientist studies things that past cultures made and used

Which individual below advocated that democracy would give way to socialism and capitalism would change into communism?

An atom of element a has 73 protons. what would the element's atomic number be?

In at least two paragraphs, discuss the differences between the principles of republicanism and democracy. explain whether you think the united states is more of a republic or a democracy. refer to at least one example from the constitution