B. Provide examples of two ways that economic ties between Mexico City and two of the larger cities in Texas, Houston and San Antonio, allow Mexico City's influence to spread to the United States.

d. new methods of assembly are introduced.

explanation:

this allows for the goods to be made on a larger scale. not faster because now it is shown to be made better, hence the greater productivity in the question. it is calling for something new to be introduced.

d. loss of habitat and farmland