People living in the cold regions of russia and finland often build their structures with to prevent them collapsing from the weight of snow.
a. slanted roofs
b. wooden walls
c. underground shelters
d. abode bricks

answer; i believe the correct answer is (fluctuated);

a mid-ocean ridge or mid-oceanic ridge is an underwater mountain range, formed by plate tectonics. this uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary.a geomagnetic reversal is a change in a planet's magnetic field such that the positions of magnetic north and magnetic south are interchanged.