Which infrastructure development in the early 1900's did the most to increase shipping between the west and east coasts of the united states?

The Panama Canal.                               dlsv;afals

radiative zone

explanation    

radiative zone is the layer of the sun which energy is transferred away from the core by radiation. although, the core is the only part of the sun that produces an appreciable amount of heat through fusion. in fact, 99% of the energy produced by the sun takes place within 24% of the sun's radius.