Sun yat sen believed china needed freedom from which of the following?
oppression
foreign invasion
foreign imperialism
foreign ideas

Sun Yat Sen believed China needed freedom from: Oppression

In order to achieve this, Sun Yat Sen created three principles that must be followed by every country to ensure that its people is free from oppression, three principles of the people, which are  

- Nationalism ,

To ensure that people are proud of their own country and willing to sacrfice for its well being

- Socialism

To ensure that even the poor citizens are taken care of by the government.

- Democracy

To ensure that majority of people can choose the leaders that truly represent their aspiration

why was the national assembly formed by the third estate?

the estates-general had not been assembled since 1614, and its deputies drew up long lists of grievances and called for sweeping political and social reforms. the third estate, which had the most representatives, declared itself the national assembly and took an oath to force a new constitution on the king.

"the royal proclamation of 1763"