An area that was covered by a glacier
Primary succession is a method of bringing about fertility in infertile land that can not be cultivated. This method usually involves plant species known as "pioneer species", that do not rely heavily on soil nutrients but add nutrients to the soil. The land under the glacier is likely to be void of nutrients and infertile, so primary succession will be needed there the most.
Description 2 describes a commensal symbiosis. The answer is D, commensalism.
Explanation:
Most volcanoes form at the boundaries of Earth's tectonic plates. These plates are huge slabs of the Earth's crust and upper mantle, which fit together like pieces of a puzzle. These plates are not fixed, but are constantly moving at a very slow rate. ... Sometimes, the plates collide with one another or move apart.