Because roots need to go towards soil as it provides food, moisture and nutrients white shoots go upward because the leaves on them need sunlight for precipitation. 
1 5 1
The Brainliest Answer!
Roots grow in the direction opposite to the light as it can go through anaerobic respiration and absorb required nutrients as well, where as shoots can only perform aerobic respiration and need to absorb sunlight in order to perform photosynthesis and thats why shoots grow in the direction of the light
1 5 1