Biomes are defined by specific characteristics. A desert.
Photo by Nomadz
What characteristics would define the biome shown?

Ibelieve the answer is relative humidity  because it makes more sense that way. solar flares usually occur in space it doesn't affect the earth, well it could but it wont make a significant damage.  latitude is land it doesnt do anything. prevailing winds, i dont know the correct meaning for this but i doubt that affects the land so it has to be relative humidity.

When plants die fungi breaks them down

The last option water because it is slow