This is a line on a map that indicates distance north or south of the equator.

there is a treasure chest with billions of gold on a sunken ship.

explanation:

i mean it is

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.