Consider the following assertion : In the Pleistocene period either the Yamuna once flowe…

Approach: *Use zoogeographical and geological evidence to explain the historical connection and river-capture events between the Indus and Ganga river basins during the Pleistocene epoch.*

- **Correct Answer:** (d) 3
- **Why Statement 3 is the correct basis:** The freshwater river dolphin (*Platanista*) is strictly a freshwater mammal that cannot survive or travel through saltwater seas. Its presence in two completely separate systems—the Indus and the Ganga—provides definitive biological proof that these river systems shared a direct freshwater connection or a common tributary during the Pleistocene period before tectonic shifts separated them.
- **Why Statement 1 is incorrect:** The *Nadi-Sukta* of the *Rigveda* provides a historical hymn-based geographical layout of rivers during the Holocene epoch (around 1500 BCE), not geological evidence of the much older Pleistocene period.
- **Why Statement 2 is incorrect:** Robert Bruce Foote is renowned as the father of Indian prehistory for his discovery of Paleolithic stone tools in Southern India and Gujarat; he did not formulate the geological theories regarding the Pleistocene diversion of the Yamuna and Sutlej.