1. How has the use of fossil fuels affected the carbon cycle? Could noncarbon energy sources replace fossil fuels and wood burning? Why or why not?
2. In what forms can plants absorb nitrogen? What are the most environmentally sound ways to provide nitrogen to plants? Why?
3. What does a plant need for optimal growth and health?
4. Compare the functions of the vascular system (xylem and phloem) of a plant to your own vascular system (heart, veins, and arteries). How are the two systems similar and different?
5. In what ways do you owe your existence to plants?
