10 questions about Avatar

1)Why is there fire in Pandora when there is no oxygen present there?

2)When the plane landed on Pandora, why did the natives there do not know about it?

3)Everything in the movie Avatar is coloured differently compared to Earth except for the trees. Why is it so?

4)When the humans are fighting against the Na'Vi, why did the humans not just kill the "Tree" straight away but choose to burn the small trees?

5)What is the Na'Vi main source of food if they are hunters but do not hunt much?

6)Is there really minerals such as unobtanium or did the director make it up? (I check the Internet and found that unobtanium can cure cancer?)

7)What is the message the author trying to convey through the movie? Is it about misunderstandings can cause war or others?

8)The Na'Vi in the movie were all very tall. Is it because of the digital effects that caused them to looked tall?

9)All the creatures in the movie were very colourful, how did the director get so many inspirations to create so many different types of animals?

10)The characters in the movies have many different features. Why did the director decide to make the characters have so many diffent features?