TeXes Science Practice Test

Which biome covers the largest area of the biosphere?

1. Desert

2. Tundra

3. Aquatic

4. Forest

The correct answer is: Aquatic

The aquatic biome covers the largest area of the biosphere. This biome includes all water bodies, including oceans, seas, rivers, lakes, and wetlands. Oceans alone make up approximately 70% of the Earth's surface, which highlights the vast extent of aquatic environments compared to terrestrial biomes. The diverse ecosystems found within the aquatic biome support a rich variety of life forms, from microscopic phytoplankton to the largest mammals on the planet, such as blue whales. In contrast, while deserts, tundras, and forests are significant biomes, their coverage on the Earth's surface is much less than that of aquatic environments. Deserts, for instance, are characterized by extreme aridity and cover about a third of Earth's land area, whereas tundra biomes, found in polar regions, are limited to specific climatic conditions. Forests, although extensive and crucial for biodiversity and global climate regulation, also occupy less area compared to the vast expanses of aquatic ecosystems. Therefore, when considering the total area encompassed, the aquatic biome undeniably takes precedence.