How do auxins cause a plant to bend toward light?

1. How do auxins cause a plant to bend toward light?  
A. They cause more cells to form on the lighted side of a stem.  
B. They cause more cells to form on the shaded side of a stem.  
C. They cause cells on the lighted side of a stem to elongate, bending the stem.  
D. They cause cells on the shaded side of a stem to elongate, bending the stem.  
2. Which kind of hormone causes fruits to ripen?  
A. Auxins  
B. Gibberellins  
C. Ethylene  
D. Cytokinins  
3. What type of hormone could you use if you wanted seeds to germinate quickly?  
A. Auxins.  
B. Ethylene  
C. Cytokinins  
D. Gibberellin  
4. Which plant response causes a stem to grow upward and a root to grow downward?  
A. Phototropism  
B. Gravitropism  
C. Photoperiodism  
D. Thigmotropism  
5. What plant response causes the leaves to change color in fall?  
A. Phototropism  
B. Gravitropism  
C. Photoperiodism  
D. Thigmotropism