Answer:
This is an incomplete question where the figure is missing.
The answer to this question is --
Directional selection
Step-by-step explanation:
In evolution, natural selection means the processes by which different forms of life having specific traits that helps them to adapt to a specific environmental changes, such as changes in climate, as predators, or competition for mates or food, will have a chance to survive and produce offsprings in more numbers than others of the same kind.
Directional selection is one type of natural selection in which the specific observable characteristics or phenotype of the specific species tends to adapt to one extreme phenotype than the other phenotypes. This will cause the allele frequency to move over time towards the direction of that specific phenotype.
Thus in the context, the directional selection shows the red solid line and black dashed line.
Hence the answer is --
Directional selection