Final answer:
The Tierra Nevada elevation zone above 15,000 feet has ecosystems with permanent snow, ice, and minimal vegetation, similar to the tierra helada zone.
Step-by-step explanation:
Areas in the Tierra Nevada elevation zone, which are located above 15,000 feet, have ecosystems that are characterized by permanent snow and ice and very little vegetation, due to the harsh climatic conditions at such high altitudes.
These areas are recognized for their minimal human activity and can be categorized alongside the tierra helada zone. This alpine environment sees no tree growth and has limited biodiversity, typically consisting of short grasses and specialized wildlife that can endure the extreme cold and high elevation.