Final answer:
In Globalization 2.0, technology, especially steam and rail power, was the primary agent of change, facilitating economic interconnectivity and advancing the global economy.
Step-by-step explanation:
The key agent of change in Globalization 2.0 (A.D. 1800-2000) was the advancement of technology, particularly the rise of steam and rail power, which revolutionized how economies were organized and how goods were transported. This era saw significant economic growth and changes in social structures as a globalizing economy became increasingly interconnected. Technology continued to play a critical role, leading to further advances such as the Internet, communication systems, and sophisticated supply chain management, propelling globalization into the post-millennial era where digital technology underpins communication and trade.