Directions: According to the information in the passage, choose the appropriate synonym for the given word.

Staples

ROMAN LAND TRANSPORTATION: THE ROMAN ROAD SYSTEM
In the Roman Empire, for the first time in history, a system of fully connected roads (and of cities connected by roads) came into existence. But, its military and administrative purposes were clear; when the question was the shipment of wheat or other bulky staples, the method used was almost certainly a relatively primitive sailing ship. Land transport was too costly of food resources to be employed in freight shipment: the justification for the extensive land transportation system of the Roman Empire was the efficiency and speed it brought over to lordship and administration.
The chariot was capable of speeds that could assure relatively quick communication if a firm and reasonably sloping surface could be had. The Romans accomplished such construction by devising a drained sub-base to be paved with fairly tight-fitting flat rocks. Few of these roads were wide enough to allow wagons to pass each other. In fact, the pavements were rather narrow for the passage of a single wagon; only chariots fitted comfortably.

Romans were not particularly successful in operating wagons or carts for the handling of freight. In common with other southern Eurasian cultures, the Romans kept oxen and knew how to employ their strength to draw loads using the horn and then the withered yoke. But they made no technical improvements on two-wheel and four-wheel carts. The wheels were rigidly fixed to the axle, forcing left and right wheels to revolve together and at the same speed but over different distances. Turning from a straight course thus forced one side to move farther than the other, dragging the wheels on one side while introducing considerable frictional resistance on the other. Furthermore, the axles were rigidly fixed to the cart's frame so any turning motion forced the cart to be dragged into a turn rather than turning into it by steering the direction of the wheels. Only the Celts had by Roman times discovered the efficiency of the pivoting front axle as well as a better harness to attach the horse to the cart.