The given question lack the choices of result that might come, however, the choices related to this question is as follows:
A. frequency of C1 will increase
B. frequency of C2 will increase
C. frequency of heterozygotes C1C2 will increase
D. frequency of both same alleles will increase
E. not enough information provided to predict
The correct answer is - option A. Frequency of C1 will increase.
Explanation:
In incomplete dominance, the relative fitness of heterzygous cases place always in between the other two allele genotype cases. In the given question, the relative fitness of C1C2 individuals is 0.9 between the relative fitness of C1C1 individuals is 1.0 and the relative fitness of C2C2 individuals is 0.8.
It is because there is no barrier to increasing the fitness of the more fit allele. The result of this is an increase in the fit alleles which is C1 here to reach equilibrium in the population.