What industry was most affected by the refrigerated railcar

The segments shown below could form a triangle.

What do most climatologists see as a major cause of rising global temperatures? a. earth's closer proximity to the sun due to its gravitational pull b. greenhouse gases produced by burning fossil fuels c. rising ocean levels caused by melting polar ice sheets d. water pollution cause by industrial waste

The original term of was descriptive of lower-class people who performed manual labor.