<span>Lipids
A lipid's function is to insulate the body and provide warmth in cold conditions. It can be concluded that a person with very little body fat gets very cold easily and a person with a lot of body fat gets very warm very quickly. </span>
Just to add on over time they have develiped a tuff outer layer to stop weather and insects from harming them.
Made of cells
<span>use of energy </span>
<span>growth </span>
<span>respond to stimuli </span>
<span>exchange of gasses </span>
<span>excretion </span>
<span>limited life span</span>
Average mass of the atoms of an element measured in atomic mass unit
