___________ rocks are the first  to be formed.

___________ have higher percentages of oxides of denser elements and silica content varies between 40 to 60 percent.

Based on their origin, the igneous rocks are classified into ________ types.

____________ rocks do not contain fossils.

On the basis of chemical composition,igneous rocks are classified into _____________.

__________ are generally lack in iron and magnesium.

___________ are also called primary rocks.

__________ rocks are less affected by chemical weathering. 

____________ are deep seated intrusion of igneous rocks.

_________ rocks are soft and layered.