question_answer 10)

(i)We cannot go to the centre of the earth (ii)Sedimentory rocks are formed from sediments (iii)Limestone is changed into marble.              

Answer:

(i) We cannot go to the centre of the earth because for this we will have to dig a hole 6000 km. deep on the ocean floor which is quite impossible. (ii)Sediments are transported and deposited by wind/water, etc. The loose sediments are compressed and hardened to form layers of rocks, which are called sedimentary rocks. (iii)Igneous and sedimentary rocks change their form under great pressure and temperature conditions to form metamorphic rocks. The same thing happens with limestone. It changes into marble under the effect of heat and pressure.