Question

Explain two reasons why the interior of the earth is still very hot

Answer 1

1. Weight of overlying materials on the crust exerts a lot of pressure towards the centre of the earth which generates  a lot of heat
2. breakdown of radioactive elements especially in the mantle region releases a lot of energy which is trapped in the interior
3. during the formation of the earth, outer parts cooled faster than the inner part

Answer 2

Radio-activity 

Answer 3

Radio-activity 

Answer 4

Radioactivity 
Weight of the overlying rock materials
3)During cooling after formation much is still retained outer

Answer 5

Due to the synrays from the sun