Consider the following statements about the igneous rocks: 1. Igneous rocks are normally crystalline in structure. 2. They occur in strata and contains fossils. 3. These rocks have no silica.Which of the statements given above isare correct?

•  Igneous Rocks:
-Igneous rocks are formed by the cooling and solidification of molten rock (magma) from beneath the earth crust.
-They are normally crystalline in structure. 
-They do not occur in strata nor do they contain fossils. 
-Igneous rocks may be sub-divided on the basis of mineral composition.
-When they contain a high proportion of silica they are said to be acid. 
-Basic rocks contain a greater proportion of basic oxides, e.g. of iron, aluminium or magnesium, and are thus denser and darker in colour.
-In terms of origin, there are two main classes of igneous rocks.
-Plutonic rocks
-Volcanic rocks.