I believe the closest related is speices and class
The most basic reason that cells are stained is to enhance visualization of the cell or certain cellular components under a microscope. Cells may also be stained to highlight metabolic processes or to differentiate between live and dead cells in a sample.
I think it may be this but not quite sure
Lipids are primarily hydrophobic in nature, but there are a large variety of lipids such as fatty acids, mono-, di-, and triglycerides, for example (check wikipedia for more examples).
<span>Proteins are polymers of amino acids. </span>
<span>Nucleic acids are polymers of nucleotides.</span>
In this case the objects must be touching