5. 6. Classify the following rocks into igneous, sedimentary and metamorphic rocks: Gneiss, Marble, Basalt, Granite, Gabbro, Slate, Dolerite, Gypsum and Sandstone.
6. Write 'True' or 'False' against the following statements: The earth has never changed in form and structure. (a) (b) Continents and ocean beds are found on the crust. (c) Molten rocks in the earth's interior are known as lava. (d) Quartz and feldspar are minerals found in rocks. (e) Granite is a primary rock. (f) The temperature of the earth rises by 1°C for every 35 metres of descent.​