Here's why:

* Tundra is a biome characterized by extremely low temperatures, permafrost, and limited plant life. It's primarily found in the high northern latitudes around the Arctic Circle. There are no tundra biomes in the Southern Hemisphere.

Let's look at the other options:

* Tropical Rainforest: Found in both the Northern and Southern Hemispheres near the equator.

* Temperate Deciduous Forest: Found in both the Northern and Southern Hemispheres in mid-latitude regions.

* Savanna: Found in both the Northern and Southern Hemispheres, typically in areas with distinct wet and dry seasons.

Let me know if you have any other questions!