This resource is a source of regional conflict due to its short supply.
petroleum
salt
water
zinc

Water because they might have a competition over it

Ithink its convection.hope this plz give brainliest!

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.