World Rivers – International boundaries Which river runs along a significant stretch of the border between the United States of America and Mexico?

Introduction / Context:
Many international boundaries are defined or influenced by rivers. In North America, one prominent river demarcates much of the border between the USA and Mexico and is referenced frequently in geopolitics and law.

Given Data / Assumptions:

• The task is to identify the boundary river.
• Several major American rivers are offered as distractors.
• We rely on well-known geography of North America.

Concept / Approach:
The Rio Grande (known in Mexico as Río Bravo del Norte) flows from the San Juan Mountains in Colorado through New Mexico, forms the Texas–Mexico border for a long stretch, and empties into the Gulf of Mexico. Other rivers listed either flow entirely within a single country or lie far from the border.

Step-by-Step Solution:
List candidates and locations: Amazon (South America), Mississippi (interior USA), Colorado (USA–Mexico boundary only in a small historical context; primarily USA).Identify the main boundary river: Rio Grande along Texas–Mexico.Choose “the Rio Grande”.

Verification / Alternative check:
Political maps clearly show the Rio Grande forming most of the Texas–Mexico line, confirming its boundary role.

Why Other Options Are Wrong:

• the Amazon: located in South America.
• the Mississippi: runs north–south within the USA; not an international boundary with Mexico.
• the Colorado: crosses the border vicinity but does not form the principal international boundary stretch.

Common Pitfalls:
Assuming any southwestern USA river marks the entire boundary; only the Rio Grande defines the major continuous section.

Final Answer:
the Rio Grande