Answer:
o Dominant/recessive genes
Cross: Rr  x  Rr  (two round-seeded plants)
F1) 25% RR, 50% Rr, 25% rr
  75% Rounded seeds, 25% elongated seeds
o Codominance
Cross: BB  x  WW (black chicken with white chicken)
F1) 100% BW
  100% speckled chickens
o Incomplete Dominance
Cross: RR  x  rr  (Red-flowered plant with white-flowered plant)
F1) 100% Rr
   100% Pink-flowered plants
Explanation:
Due to technical problems, you will find the complete answer and explanation in the attached files