Final answer:
The Indus River was the most significant geographic feature for the flourishing of ancient Indian civilization, providing fertile land for agriculture and supporting advanced urban societies.
Step-by-step explanation:
Geographic Feature Central to Ancient Indian Civilization
The most important geographic feature to the thriving of ancient Indian civilization was the Indus River. This river created fertile plains crucial for agriculture, enabling the Harappan civilization to flourish during the Bronze Age. Not only did the people of the Indus River valley develop advanced urban planning skills, but they also engineered complex water resource systems including reservoirs, bathhouses, and restrooms. Additionally, the river supported a rich agricultural base with crops like wheat, barley, and millet. This agricultural surplus allowed urban centers such as Harappa and Mohenjo-Daro to prosper and become some of the ancient world's most technologically advanced cities.
Furthermore, the presence of abundant water from the Indus River contributed to the specialization of labor, irrigated agriculture, and the rise of a merchant class that engaged in far-reaching trade routes. However, environmental degradation such as deforestation and soil erosion eventually led to the decline of these urban centers around 1700 BCE.