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.
The word igneous comes from the Latin for fire, and what igneous rocks have in common is that they formed by the cooling and crystallization of a melt. This material may have been lava erupted at the Earth's surface, or magma (unerupted lava) at depths of up to a few kilometers, or magma in deeper bodies (plutons).ranite is the light, coarse-grained rock formed at depth and exposed after deep erosion. It is rich in feldspar and quartz (silica) and hence is called a felsic rock. So granite is felsic and plutonic. Basalt and granite account for the great majority of igneous rocks.