Define permafrost.
a. water below the surface of the tundra stays frozen all year long
b. the frozen soil in mountain highlands
c. rainwater that collects on rocks after a cold rainstorm
d. the dew droplets that freeze at high altitudes

1. crust 1 the metallic layer at the earth's center 2. inner core 3 the firm layer between the crust and the asthenosphere 3. lower mantle 2 the layer surrounding the inner core 4. asthenosphere 4 the semi-solid layer between the top layer and the upper mantle 5. upper mantle 5 the layer between the asthenosphere and lower mantle 6. top layer 6 the earth's outermost layer 7. outer core 7 the hottest part of the mantle

Which mountain range separates georgia from russia? a. ural mountains b. carpathian mountains c. caucasus mountains d. siberia mountains

The force of gravitational attraction between the sun and venus could be increased by reduseing which of the followinga. the distance between the sun and venus b. the period of rotation of the sunc. the mass of the sun and venusd the speed of the orbit of venus