Final answer:
The Han dynasty's invention of long iron swords greatly improved military efficiency and agricultural productivity, leading to economic growth and social changes, such as the rise of a new class of merchants and a more diversified economy with an expanded iron industry.
Step-by-step explanation:
The Han dynasty was renowned for its technological innovations, which significantly impacted various areas of society. Amongst the notable advancements were the long iron swords and other iron tools which enhanced both military capabilities and agricultural productivity. Iron's utility extended beyond prestigious items to become a fundamental component in improving social infrastructure; from household cookstoves to agricultural tools, it revolutionized daily life and boosted the economy.
Notably, the assimilation of iron technology in warfare catalyzed a surge in economic growth during the late Zhou period. This era witnessed a rise in agricultural productivity, the establishment of new irrigation channels, and facilitated a burgeoning merchant class aspiring for social ascension through merit and bureaucratic service. The iron industry also evolved, seeing a significant increase in production and the adoption of alternate fuels like coke for smelting, which expanded employment opportunities beyond traditional agricultural work.