Final answer:
Selection violates the assumption of no selection in Hardy-Weinberg equilibrium, leading to changes in allele frequencies.
Step-by-step explanation:
In the context of biology, the concept of selection refers to the process by which certain traits or alleles become more or less common in a population over time. In the Hardy-Weinberg equilibrium, the assumption of no selection means that there is no change in the distribution of alleles due to selective pressures. However, if selection is occurring, it violates this assumption and leads to changes in allele frequencies. In conclusion 2 for the 'no selection assumption,' selection would be considered a violation because it introduces changes in allele frequencies.