Please help me with these questions I have looked all threw my book but i cant find them.

Question

7. Why are we not sure about the interior of the earth? Do we know for sure why?

12. Some volcanoes are more explosive than others? What makes this diffrence in explosivity occur?

14.What is the elastic rebound theory? Why do fences off set during an earthquake?

Please help me I am getting a headache from looking so much.

Answer 1

I found some info on wikipedia about this subject(just google for volcano+wikipedia)

Basically, the explosive power of a volcano depends on the composition of its magma. If the magma contains high amounts of silica (>63%), gases are trapped within, and cause enormous explosions. Other volcanoes containing less silically will tend to be far less destructive.

Answer 2

We are not sure of the core because we havent dug that far but we due know there is magna and copper I think, some mat. We also know it has a little grvitation pull holding us to earth
I hope this helps you I also am doing biology homework and cannot figure out this probability I know its easy I just need some one to refresh my memory I ahve all the #'s I need to plug in just staring at me giving me a head ache o wel GL