Which step of a biogeochemical cycle exposes soil to water, carbon, and nitrogen at the same time? Precipitation
Transpiration
Evaporation
Fixation

Hi, There! First Let's Look at the Defintion of Biogeochemical↓

Biogeochemical cycle, any of the natural pathways by which essential elements of living matter are circulated.

Now Below We Have the Meaning of biogeochemical Cycle↓

Biogeochemical cycles (definition) the cycles that move water, carbon, oxygen, and nitrogen through living and nonliving parts of the ecosystem

Well you First Option is Precipitation which Is  one of the three major parts of the global water cycle. Precipitation forms in the clouds when water vapor condenses into bigger and bigger droplets of water. ❌

Transpiration is the loss of water from a plant in the form of water vapor ❌

Here we have the Meaning of Water cycle

The water cycle is the path that all water follows as it moves around Earth in different states. Liquid water is found in oceans, rivers, lakes—and even underground

My Answer would be Evaporation✅

Evaporation is the most appropriate option .