You can fill the sides with any allele.
After that the first box will be the dominant allele than the recessive allele, the box below that will be the dominant allele and the recessive allele. Dom being capitol and recessive being lowercase, the box on the top right will be dominant allele and recessive and bottom dominant and recessive. It’s all based on the allele of that row and column.
The dodo was placed in the animalia kingdom because it corresponds to all the characteristics that define it as part of it.