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. 8 km, 10 km
3. 10 km, 60 km
4. 10 km, 40 km

The entire core is about …………….. km in diameter.

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

The average thickness of Mantle is ……………… km.

1. 2500
2. 2700
3. 2900
4. 2300