The variable that does not affect biome distribution is soil type. While soil type can influence the specific plant and animal communities within a biome, it is not the primary factor determining the overall biome distribution.

Here's why:

* Climate is the primary driver of biome distribution. Temperature and precipitation patterns determine which plant and animal life can survive and thrive in a particular region.

* Latitude and altitude also play a significant role in shaping climate, and therefore biome distribution.

* Ocean currents influence regional climate patterns, impacting biome distribution along coastlines.

While soil type can affect the specific types of plants that grow in a region, the overall biome type is largely determined by climate. For example, both tropical rainforests and deciduous forests can have different soil types, but they are both defined by their specific climate conditions.

Let me know if you have any other questions!