In West Virginia many companies specialize in mountaintop removal mining where bulldoze the the top of mountains in order to extract coal from the rock

the following answer in the following answer

answer; seasons change because earth tilts on its axis; and the angle of the tilt causes the northern and southern hemisphere to trade places throughout the year;

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.