What does chemical activity mean? answer quickly

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

Each pair of clay balls represents to planetesimals if each plane test molluscum pound of the same material and is separated by the same distance which pair experiences the greatest gravitational attraction

Which of these expressions are correct variations of the combined gas law? p1v1t2 = p2v2t1 both