Filamentous actin is polar and, therefore, the two ends of the filament are different. Because of this polarity, the filaments often fit into other cellular structures in only one orientation, in a similar manner to how many of the parts of man-made structures are assembled. Growth, the addition of monomeric actin to the filament, occurs predominantly in one direction; the plus direction.
Larger landscaping rocks, such as boulders, can cost upwards of $800 per ton. For example, a volcanic rock can cost $600 per ton, and an Artic white boulder can cost $150 per ton. Natural stone edging, ideal for gardens and walkways, can cost $200 to $600 per ton.
Spray the rocks with water to remove as much of the surface debris as possible. You don't have to scrub each rock with a brush, but you'll find it easier to get rid of the rock if you make an effort to remove any soil, leaves or grass debris. Offer the landscaping rocks to your neighbors first. If they have use for them, they can usually take them quickly. In addition to asking neighbors with whom you are friends, you can offer them at your next homeowner's association meeting or community event.