In terms of particle movement and energy what occurs when a solid is heated to its melting point

Which statement describes the appearance of a temperature-vs.-time graph? a horizontal line shows that the temperature increases at a constant rate over time. a vertical line shows that the temperature decreases at a constant rate over time. horizontal lines where the temperature is constant during phase changes connect upward-sloping lines where the temperature increases. horizontal lines where the temperature increases are connected by upward-sloping lines where the temperature is constant for each phase.

Which sentence best describes the formation of igneous rock? a- lava on the surface dries up and makes arock b_melted rocks cools and forms crystals c_rocks under tremendous heat and pressure d_magma is melted rock underground

1) this is the structure in the cell nucleus that houses a cell's genetic information