The answer is the first one (A): Biomes.
Explanation for each option:
A. Biomes - Correct. Biomes are large regions characterized by specific types of climate, flora, and fauna. They encompass various ecosystems and are defined by factors such as temperature, precipitation, and the types of organisms that live there.
B. Desert - Incorrect. A desert is a specific type of biome characterized by low precipitation and arid conditions. It is not a general term for large regions with distinct climates and species.
C. Tundra - Incorrect. Tundra is another specific type of biome, known for its cold climate and limited vegetation. It is not a general term for all large regions with distinct climates and species.
D. Grassland - Incorrect. Grassland is a specific type of biome characterized by vast open spaces dominated by grasses. Like desert and tundra, it is not a general term for all large regions with distinct climates and species.
In summary, the term "biomes" refers to large regions with their own climate and species, making option A the correct choice.