I'm doing an acrostic poem about river processes for geography and i can't think what to put next, i need a sentence starting with o and s.

How are farmers that use no plow farming methods able to improve air quality for the people around the fram

1. crust 1 the metallic layer at the earth's center 2. inner core 3 the firm layer between the crust and the asthenosphere 3. lower mantle 2 the layer surrounding the inner core 4. asthenosphere 4 the semi-solid layer between the top layer and the upper mantle 5. upper mantle 5 the layer between the asthenosphere and lower mantle 6. top layer 6 the earth's outermost layer 7. outer core 7 the hottest part of the mantle

The economies of nordon could be described a. unable to use rich resources b. struggling but diverse c. dependent on one product d. healthy and diverse