In the southern european plains, a species of flower comes in two colors, purple and pink. when pink flowers are most common in a field, bees visit and pollinate the purple flowers more often, and vice versa. this switching of pollinator preference will result in

It will result in Negative frequency-dependent selection.

Frequency-dependent selection is when the fitness of a phenotype depends on the frequency of the other phenotype in the population. In this case is negative frequency-dependent selection, because the fitness of a phenotype(pink) decreases as it becomes more common.

Nucleus is the organelle that contains chromosomes