The persistence and perseverance of american homesteaders in the late 1800s led to an expansion of the frontier. delayed railroad construction for decades. brought about the closing of the frontier. was fruitless in the face of so many difficulties.

the correct answer would be C. it brought about the closing of the frontier

hope this helps! :)

the answer to the question is C

seeing as no choices were provided, i'll do my best to answer it from knowledge.

job specialization promotes work ethic to the person doing the job. he/she may be strong in the arms and able to lift things, specializing him/her in a job where you lift and carry.