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.
1 Louisvilleky.gov received bids from five different contractors, whose rock excavation services were priced anywhere from $60 per cubic yard by blasting, to as much as $125 per cubic yard by mechanical means.t may also refer to the removal of undesirable rocks from a certain area. Rock excavation is not a new practice at all. In fact, it has been used in the construction industry since the invention and widespread use of dynamite in the 19 th century.