Why American Government Have Two Major Parties Questions

Why does the United States have only two major political parties at the national level? Demonstrate your understanding of why we have a two-party system in a 3 to 4 paragraph (well-cited and argued posting).

If possible, answer the two questions, no paragraphs required.

1) How many “Third” party politicians have served in the U.S. Senate in the last 20 years?

2) The head of state of Denmark belong to which political party?