When you put a teapot on the stove to boil water, which of the three kinds of heat transfer can be observed?

tracks, burrows, eggshells, nests, tooth marks, or gastroliths

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.