As you can see in the picture presented below, the three classes of water have distinctive traits.
Pure substances contain only one element, they are not mixtures of different things.
The homogeneous mixtures have multiple elements, but they are so well blended together that you can't easily observe or separate them.
In heterogeneous mixtures, we can easily differentiate between different elements of the mixture.
The answer is Catecholamine. It is any of a class of aromatic amines that includes a number of neurotransmitters such as epinephrine and dopamine. The adrenergic receptors are a class of G protein-coupled receptors that are targets of the catecholamines, especially norepinephrine (noradrenaline) and epinephrine (adrenaline). These three - catecholamine, peptide hormones and eicosanoids acts as extracellular membrane receptors which means that these receptors are embedded in the membranes of cells. They act in cell signaling by receiving (binding to) extracellular molecules.
They are different from each other because ones in forest and ones in the desert