What life sustaining unit contains only one per cent of the earth's mass?

1. biosphere
2. lithosphere
3. crust
4. mantle

Mohorovicic discontinuity is found at about …………… beneath the oceans and …………… beneath the continents.

1. 8 km, 32 km
2. 36 km, 10 km
3. 60 km, 6 km
4. 40 km, 4 km

The diameter of the core is about …………… km.

1. 5000
2. 6000
3. 7000
4. 8000

Name the layer of the earth that is fragile as compared to the rest of the layers of the earth. Different theories suggest that this layer undergoes changes to give earth a new shape.

1. Mantle
2. Core
3. Crust
4. Asthenosphere