Codominance. Both alleles are expressed and neither one inhibits the other.
(C)theories can be used to predict the existence of as of yet unobserved things or phenomena
Answer - The chromosomes has to be crucially duplicated and it happens actively during the resting phase or interphase.
Reasoning - During the resting phase or interphase you call it, Is important to have the same exact DNA or Chromosomes to be duplicated. If the chromosomes did not duplicate during the interphase then the split of the cell would be unbalance and uneven and likely to cause defects.
The heterozygous birds phenotype would therefore be black and white because both parent genes are dominant so they would be fully expressed,none would overpower the other(no dominant or recessive) this is known as Codominance and and example of this is with the blood types.
C. Sperm is produced in a male organism by meiosis