The primary factors which determine each biome are: (Multiple choice) A. Land features.
B. Plate tectonics.
C. Sunshine.
D. Rainfall.
E. Temperature.

The primary factor which determines a biome is the climate. Temperature and precipitation essentially determines what kind of growing season or soil quality the terrain may have,which therefore affects the growth of plants living there.

explanation:

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.

that is wrong, its not thymus.