UGC NET Questions (Paper – 1)

Carrying capacity links population size with long-term availability of resources and waste-absorbing capacity. It asks how many individuals can be sustained while maintaining ecological balance. Beyond this limit, resource stocks are depleted and environmental quality declines, undermining future support capacity. The focus is therefore on indefinite support, not short-term crowding.

Option A:
Option A is incorrect because physical crowding alone does not indicate sustainability; a dense city may still operate within or beyond ecological limits depending on its metabolism.

Option B:
Option B is correct as it combines the idea of a maximum population with the requirement of not degrading underlying resources over time.

Option C:
Option C is incorrect since carrying capacity is not about keeping birth rate high; it is about sustainable support.

Option D:
Option D is incorrect because a zoo is a managed facility, not the kind of self-regulating ecosystem the concept usually addresses.

The planetary boundaries concept proposes quantitative limits for processes such as climate change,biodiversity loss and nitrogen cycles beyond which the Earth system may shift into less hospitable states. Staying within these boundaries is considered essential for sustainable development. Since the stem refers to safe operating limits for key Earth system processes,the correct term is planetary boundaries. It emphasises the global scale of these thresholds.

Option A:
Planetary boundaries integrate scientific understanding of Earth system dynamics with normative goals of avoiding catastrophic change. They provide a framework for discussing global environmental governance. This scope matches the description in the question.

Option B:
Continental boundaries would refer to limits at the scale of individual continents,rather than the entire planet. The concept in the literature is explicitly planetary,so continental is not accurate.

Option C:
Local boundaries might apply to smaller ecosystems or regions,but the framework asked about in the stem is global in nature. Therefore local cannot fill the blank correctly.

Option D:
Hydrological boundaries relate specifically to water systems and watersheds. While freshwater use is one planetary boundary,the overall concept extends beyond hydrology,so this option is too narrow.