Lichens are typically the first organisms to colonize bare rock. They are therefore the pioneer species in primary succession. Many organisms require soil before they can colonize an area. Lichens that colonize bare rock secrete acids that break down the rock and start the soil-production process. Also, as lichens die, they provide some organic matter that also contributes to soil.
Division is defined as separation or a difference of opinion. 1  An example of division is when you break up a set of bookends into two pieces. 2  An example of division is when people within a political party disagree about the passage of a bill.  a dividing or being divided; separation.
From Wikipedia, the free encyclopedia. 50 Divisions refers to the 50 divisions of construction information, as defined by the Construction Specifications Institute (CSI)'s MasterFormat.