During testing you will have 32 minutes to answer questions about several passages. Following is a sample reading passage and associated questions. Answer each of the questions about the following passage. In primary succession, such as occurs on a rocky outcropping, the sere begins with hardy, drought resistant species, often called primary organisms . Lichens are often the first to invade rocky outcroppings, held fast by their tenacious water-seeking, fungal component.
Lichens are soil builders, producing weak acids that very gradually erode the rock surface.
As organic products and sand particles accumulate in tiny fissures, opportunities arise for plants such as grasses and mosses to establish themselves and begin a new seral stage. Plant roots penetrate the rocky crevices, exerting a remarkable turgor pressure, prying at the rocks and gradually widening the fissures. By then, certain insect and reducer populations will also have established themselves. In time, the lichens that made the penetration of plant roots possible are no longer able to compete for light, water and minerals and they give way to the plants. Similarly, these plants will contribute to the soil building for a time, and then they too will be replaced by fast-growing shrubs, and new populations of animals will invade.