Define 'nation' and correct the spelling of 'achieve', 'believe', 'embarrass', 'forty', 'interrupt', 'knowledge'.

Here are the answers to the questions:

a) What is a nation?
A nation is not solely defined by geographical boundaries. It consists of a common idea or belief shared by a group of people.

b) Correct the spelling of the words:

1. acheive $\rightarrow$ achieve
2. beleive $\rightarrow$ believe
3. embarass $\rightarrow$ embarrass
4. fourty $\rightarrow$ forty
5. interupt $\rightarrow$ interrupt
6. knowle... $\rightarrow$ knowledge