21. The frost line varies throughout the country. 22. In the USA frost lines can range from just under the surface to more than 40 inches. 23. To overcome this, breeding efforts have focused on deeper rhizomes that can survive below the frost line . 24. Differentiation between these two classes of planetesimals arise due to the frost line of the solar nebula. 25. Footings placed below the frost line will be stable because they will not be affected the freeze-thaw cycle. 26. Many others burrow deep into the soil or head for the bottom of a lake, below the frost line . 27. Other surfaces include solid matter in combinations of frost line , while closer to the sun, rock and regolith predominate. 28. The 3-foot depth is necessary to get the footings below the frost line , to prevent heaving in the winter. 29. Quaker Oats Co . expects its new Gatorade Frost line will add $ 100 million in revenue this year. 30. Finally, in tropical regions, frost line may refer to the vertical geographic elevation below which frost does not occur.
