Growth in the use of railroads was made possible by?

a. production of reliable maps
b. development of accurate timekeeping
c. improvements in iron and steel production
d. agreement with canal and streetcar interest.

C-improvements in iron and steel production

Maps did not have a huge factor in the growth of railroads

Timekeeping also did not.

D is also an incorrect answer

therefore it is C

C. Improvements in iron and steel production

Explanation:

As soon as Iron and Steel production got cheaper, easier and better the construction of Railroads, which depended largely on the use of this primary resources to work in their construction growth in the use of railroads was made possible when it starter to get cheaper to build them, and the new processes cut the prices of the primary resources needed for its construction.

- three-quarters or two-thirds..

- "the constitution provides that an amendment may be proposed either by the congress with a two-thirds majority vote in both the house of representatives and the senate or by a constitutional convention called for by two-thirds of the state legislatures."

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hernan cortes;

explanation: