Why did trees grow in New England and New York, while grasses coat Oklahoma, shrubs cover the tundra, and cacti dot the desert? ... Additional water transpires through the pores in their leaves. ... So most of our trees, like those in the tropical dry forests, lose their leaves in order to conserve precious moisture. Plants that retain their leaves, like the mountain laurel or the pines, usually have thick, heavily waxed leaves that retain moisture exceptionally well. ... Over time decaying wood and leaves will enrich the soil. ...

• Word Count: 2774
• Approx Pages: 11
• Grade Level: High School