A. Tick the correct option. 1. Living organisms do not survive inside the earth due to Answer: high temperature 2. Earthquakes and volcanoes are caused by Answer: internal disturbance 3. Respective layers of the earth from top to bottom are Answer: crust, mantle, core 4. The full form of SIMA is Answer: silica and magnesium 5. The original rock from which Gneiss formed is Answer: granite B. Fill in the blanks. 1. Earth was formed about ___________ million years ago. 2. The behaviour of ___________ waves tell us about the earth’s interior. 3. The ___________ of crust varies from place to place. 4. Rocks are classified into three groups on the basis of their ___________. 5. The ___________ of the earth is rich in iron and nickel. Answer: (1) 4600 (2) seismic (3) thickness (4) formation (5) core C. Give a single term for each of the following statements. 1. It is the hardest substance. 2. The molten rock material present inside the earth. 3. Rocks...