What are biomes?

Biomes are large ecological areas on the Earth's surface characterized by specific climate conditions, soil types, and distinct groups of plants and animals adapted to those environments. Each biome is defined by the types of vegetation and the animal species that inhabit it, which have developed over time due to the adaptations needed for survival in that particular climate. Understanding biomes is crucial for studying ecosystems, biodiversity, and the impact of global changes like climate change on different regions.

The other options refer to concepts that do not relate to the ecological definitions and characteristics of biomes. For instance, populated cities with diverse cultures focus on human geography and sociocultural dynamics rather than the biological and ecological aspects. Legal boundaries and systems of government pertain more to political geography and land management instead of ecological classifications. Thus, the answer clearly highlights the biological dimension that defines what biomes are.