Question

Study the diagram and answer the following questions:

1. Identify the types of rocks shown in the diagram.
2. Arrange the rocks according to their chronology of origin.
3. Explain how sedimentary rocks are formed.
4. Think of all the factors which may break the rocks into smaller pieces.
5. Which type of rock will break easily as compared to others? Why?

Answer 1

1. Igneous, sedimentary, and metamorphic rocks are shown in the diagram.
2. Igneous, sedimentary and metamorphic rocks.
3. Sedimentary rocks are formed from layering upon layering of all the organic (dead remains of plants and animals) and inorganic (sand, silt, clay, gravel, etc.) material in a depression or on the low lying area. If there are cementing materials like limestone, hardening, and compaction take place, then sedimentary rocks are formed.
4. Heat, pressure, water, wind, animals, plants, etc., can break rocks into smaller pieces.
5. Sedimentary rocks will break easily as they are formed by the layering of sediments and thus, they are soft and porous and are broken easily. 

• Igneous rocks are formed from the cooling and solidification of molten magma; hence they are hard and non- porous.
• The metamorphic rocks too cannot be broken easily as they are formed from heat and pressure.
• The metamorphic rocks too cannot be broken easily as they are formed from heat and pressure.