Which statement tells what happens during the rock cycle when rocks undergo great heat and pressure? a. igneous rock is formed. b. metamorphic rock is formed. c. rock is melted. d. sediments are lithified to form new sedimentary rock.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.