How do you define personal responsibility? When something bad happens that involves you, how do you know whether or not you bear some responsibility for it?

I would define personal responsibility by taking responsibility for one's actions. For example, turning in homework assignments, or keeping a promise and ones word. Responsibility is a particular trouble of obligation upon one who is responsible, also trustworthiness or loyalty. 

When something bad happens that involves me, I take responsibility either way. For example, There was a time I gave my brother permission to go to the park without my parents consent. The responsibility fell on me because, I didn't ask permission for him, nor did I watch him. So when something bad happens that involves me I am required to take responsibility. 

Questions for English

What are some ways in which people throughout the ages have explored the unknown?
~Some ways that people throughout the ages have explored the unknown is by simply dreaming about the unknown. Long ago people used to think there was only one world. Until new explores decided to explore the rest of the world. To there excitment they discovered "the new wrold". Which gave way to new settlers and soon created a new country.
Why have individuals devoted themselves to a life of exploration and discovery?
~Individuals have devoted themselves because either to ecape a horrible life lived in a certain cournty, or to spread they're beliefs and religion to other individuals.
What sacrifices does such devotion involve?
~These sacrfices involve either leaving their whole life behind in search of a new one, or leaving the people he/she loves behind.