Laryngomalacia is the most common cause of chronic stridor in children younger than two years. It has a male-to-female ratio of approximately 2:1.1 The condition is due to an intrinsic defect or delayed maturation of supporting structures of the larynx.
Volcano Rocks Igneous Rocks. Introduction Volcano rocks are igneous rocks that form during a volcanic eruption. They were all once magma which is molten rock beneath the Earth's surface. There are four major groups of the igneous rocks: basalt, andesite, dacite and rhyolite. Each of these different rock groups form different types of volcanoes. Volcanic rocks forming during eruption of Kilauea, USGS Rhyolite rocks Rhyolite magma cooling underground forms granite.
Igneous rocks are classed on the basis of where they form and the compostion of the molten rock. Igneous rocks form from molten rock which is either ejected at the surface of the earth or cools off underground.When volcanoes erupt, they can eject molten rock as shown in the following picture.This hot, thick lava flows down the side of the volcano and eventually cools.gneous rocks form from molten rock which is either ejected at the surface of the earth or cools off underground. When volcanoes erupt, they can eject molten rock as shown in the following picture.