Water<span> issuing from a </span>hot spring<span> is heated geothermally, that is, with heat produced from the Earth's mantle. ... The rate of temperature increase with depth is known as the geothermal gradient. If </span>water<span> percolates deeply enough into the crust, it will be heated as it comes into contact with </span>hot<span> rocks.</span>
The answer is because biology is easy and they're known around the world.
The electrical impulse travels across the axon, and the myelin sheath helps to increase transmission speed.
Primary succession occurs<span> in essentially lifeless areas or regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier. Hope this answers the question.</span>