Earth has been cooling since its formation, if this is the case, why is it still hot inside? A Peridotite xenoliths
B Planetesimals crashing into each other
C Radioactive decay
D Seismic waves

Idon't bro i wish i could i'm so sorry

Ibelieve it's the pacific islands 

Ithink a hope that

The answer is c, i, iii, and iv. this is because farming and mining deal with harvesting raw materials, construction work falls under manufacturing, and piloting a plane is a service. ii is wrong because making bread is using  raw materials to produce goods, which would fall under the secondary sector, not primary.