Question

Give reasons
1). We cannot go to the centre of the earth
2). Sedimentary rocks are formed from sediments
3). Limestone is changed into Marble

Answer 1

Hint: The structure of the Earth has four major components-the crust , the mantle , the outer core and the inner core. Each of these layers have unique chemical and physical properties and impact life on Earth’s surface.

Complete answer: 1)We cannot go to the centre of earth as the centre of the earth would have extreme pressure and temperature. Scientists have calculated the distance to the centre of the earth to be around 6371km and no technology has been made yet to travel that deep into the earth.
2)Sedimentary rocks are formed from sediments of organic matter and minerals as they accumulate and undergo sedimentation. The sedimentary rocks are further classified into: Clastic Sedimentary Rocks, Chemical Sedimentary Rocks, Biochemical Sedimentary Rocks, and Organic Sedimentary RocksThe process of erosion, weathering , dissolution, precipitation and lithification ultimately lead to sedimentary rocks.
3) Limestone is changed into Marble when put under heat and pressure. Limestone is a sedimentary rock and calcite in the limestone changes and fossils and layering in the original limestone disappear as interlocking grains grow when put under heat and pressure. Thus marble is a metamorphic rock formed from a sedimentary rock.

Note: The other two kinds of rocks are igneous and metamorphic rocks . Sedimentary rocks are found closer to the Earth’s surface than igneous and metamorphic ones.Another point to note is that if the limestone is pure then white marble is formed.