The temperate grasslands of South eastern Europe :

Concept: Earth's temperate and cold biomes are classified by climate, vegetation cover and location. A mid-latitude, semi-arid, continental-climate grassland -- cold winters, warm-to-hot summers, and seasonal rainfall enough for grasses but not forest -- is formally named a 'Steppe' in physical geography, distinct from the boreal coniferous forest ('Taiga'), the treeless permafrost biome ('Tundra'), and the generic descriptive term 'Meadows' for any grassy field.

Application: South-Eastern Europe -- the Pannonian Basin/Hungarian Puszta and the Balkan interior, continuing into the Pontic-Caspian belt of Ukraine and southern Russia -- lies within this mid-latitude continental climate zone. Its characteristic temperate grassland is therefore specifically named the Steppe, matching the saved answer.

Cross-check -- why each distractor fails:

• Taiga: a coniferous FOREST belt of high-latitude Siberia/Canada/Scandinavia -- a forest, not a grassland, and at a far colder, higher latitude than South-Eastern Europe.

• Tundra: a treeless, permafrost-covered polar/sub-polar biome -- again a colder, higher-latitude zone, not the temperate belt in question.

• Meadows: a generic word for any grassy patch, not a formal biome/region name -- it does not specifically denote South-Eastern Europe's grassland.

Result: the temperate grasslands of South-Eastern Europe are formally called the Steppes, confirmed by standard physical-geography references (Oxford Learner's Dictionary, National Geographic, and the European Environment Agency's habitat classification).