During the mid-1800’s Chinese immigrants to the United States were an important source of labor for which of the following industries? a Railroad construction
b Steel manufacturing
c Oil production
d Ship Construction​

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.