Using the CER writing strategy, describe why rocks found at the bottom of a river are smooth and flat. Someone please do this for me because it is due in 10!!!

Answerleveling;

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.

The correct answer is:   [b]:   "physical systems" .

Ithink its d.stratum