The spacing of contour lines indicates the topography of the land surface. This can be especially helpful when planning a hike as it gives an indication of whether the hike will be uphill, downhill, some of each, or flat. In a steep, rugged terrain, contour lines will be close together. In flat terrain, contour lines will be far apart.

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.

helen told me that she hoped i had enjoyed myself.