Fact 1: Plants exhibit phototropism, or growing toward a light source.

Fact 2: Light comes from the sun.

Given the two facts above, answer the question "What is plant's tendency to grow toward the sun called?" with the following options: 
- photomorphism
 - phototropism
 - photosynthesis
 - peachleaf willow
 - Conifers
 - Exfoliation
 - vegetation
 - photochromic


 

  phototropism       