I believe the answer is incomplete dominance. Incomplete dominance creates a mix of the two phenotype(white and dark purple flowers) to create a third phenotype (lavender). Lavender is a mix.
Whereas, co-dominance would not be a mix but both traits would exist within the organism. In your question, it would be codominance if the dark purple flower and the white flower created a flower with white and dark flower pedals. This would not be a mix of the phenotype, but a co-existance of both phenotype.
This is because the GP120 protein
of the HIV virus that forms the ‘knob’ is
essential for the infection of CD4 cells
of the immune system by the virus. The glycoprotein is, therefore, a good
target for vaccines especially since the
molecule is highly conserved because most mutations in the region could be highly deleterious to the virus.
