A) In what ways can Earth be considered “an island”? (HINT: Make notes on describing the earths composition in relation to the amount of water present on earth)

b) Describe the various spheres that exist on this earth. (HINT: Pay particular attention to the earth’s distribution of gases in the earth’s atmosphere. Which gas is the most abundant? Which one is the next most abundant?)

because the center-south is called the heart of the country

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.