Geothermal energy is heat derived within the sub-surface of the earth where humans use water and its heat to have steam carry the geothermal energy to the Earth's surface; and while it is a great renewable resource, some disadvantages are that it releases some greenhouse gases and can cause earthquakes.
True or False

Which statement best describes the superposition principle? a.) if two in-phase waves arrive simultaneously at a point, their amplitudes add up b.) if two out-of-phase waves arrive simultaneously at a point, their amplitudes add up c.) if two in-phase waves arrive at a point one after another, their amplitudes add up d.) if two out-of-phase waves arrive at a point one after another, their amplitudes adds up