1. What is the rhizosphere? 2. When we think of roots, we naturally think of absorption: the absorption of water and minerals from the soil. However, roots do other things, too. Explain two other root processes described in this article.

3. Describe the main similarities and differences between the the relationship between a legume and rhizobia and the relationship between a fungus and a plant.

4. The rhizosphere greatly influences root structure, but what other factors also influence root structure? List at least three.