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.
Summary: 1.Igneous rocks are formed when magma (or molten rocks) have cooled down and solidified. Sedimentary rocks are formed by the accumulation of other eroded substances, while Metamorphic rocks are formed when rocks change their original shape and form due to intense heat or pressure..Examples of Igneous rocks include granite and basalt, while examples of Sedimentary rocks include shale, limestone and sandstone. Common examples of Metamorphic rocks are marble, slate and quartzite.