Answer:
The continuous variation
Explanation:
There are two types of variations, i.e. discrete and continuous. The discrete variations are controlled by single genes. The presence of the gene states if the variation exist or do not exist. An example is the human blood group (A positive, B positive etc.).
On the other hand, continuous variation is controlled by multiple genes (polygenic). Such types of variations are shown (plotted) in the form of histograms. An example is the height of humans which varies significantly among individuals.
