The answer is flow of heat
In order of increasing energy,
2s < 3p < 4s < 3d
<span>1.All living things are made up of cells.
2.Cells are made up of proteins and organelles.
3.Groups of cells form tissues and systems.
4.The main purpose of a cell is to organize.
<span>5.The longest cells in the human body are the motor neurons</span></span>