The first half of the twentieth century saw a increase in the development of ___ in the united states. after world war ||, many major cities linked to the suburbs by ___ a. rail roads
b. road ways
c airways
QUCIK

The answer is c epicenter

The answer is d., a mountain.

Answer(say);

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.