Why is water the least expensive mode of transportation?

What will be an ideal response?

Answer: Networks of waterways, oceans, rivers, and lakes let water carriers reach many areas throughout the world. Boats and barges are used mostly for moving bulky products. Unfortunately, water is one of the slowest modes of transportation. Speed of delivery is a major factor when considering the cost of transporting physical goods-air is the fastest and most expensive, whereas water is the slowest and least expensive.