(a) ans=Extrusive igneous rocks, also known as volcanic rocks, are formed at the crust's surface as a result of the partial melting of rocks within the mantle and crust. Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks. They are formed by the cooling of molten magma on the earth's surface.

(b ) ans=Sedimentary rocksare the product of 1) weathering of preexistingrocks, 2) transport of the weathering products, 3) deposition of the material, followed by 4) compaction, and 5) cementation of thesedimentto form arock.

(c ) ans=Intrusive igneous rockscrystallize below Earth's surface, and the slow cooling that occurs there allows large crystals to form.Examplesofintrusive igneous rocksare diorite, gabbro, granite, pegmatite, and peridotite. Extrusiveigneous rockserupt onto the surface, where they cool quickly to form small crystals.

>65Ma

Igneous rock(derived from theLatinwordignismeaning fire), ormagmatic rock, is one of the three mainrock types, the others beingsedimentaryandmetamorphic. Igneous rock is formed through the cooling and solidification ofmagmaorlava. The magma can be derived frompartial meltsof existing rocks in either aplanet'smantleorcrust. Typically, the melting is caused by one or more of three processes: an increase intemperature, a decrease inpressure, or a change in composition. Solidification into rock occurs either below the surface asintrusiverocks or on the surface asextrusiverocks. Igneous rock may form withcrystallizationto form granular, crystalline rocks, or without crystallization to formnatural glasses. Igneous rocks occur in a wide range of geological settings: shields, platforms, orogens, basins, large igneous provinces, extended crust and oceanic crust.

d ). Granite is an example of such a rock. Grindingstones used to prepare paste/powder of spices and grainsare made of granite.

this is workbook S.S.T