When a red flowered Mirabilis jalapa plant I was crossed with that of white flowered plant II then in the offspring only pink coloured flowers appear on plant. Which of the following phenomena correctly explain this experiment and result?

Correct option is B

Correct Answer: (b)
Explanation:
Red × white → pink offspring is a classic example of incomplete dominance, where the heterozygote shows an intermediate phenotype (blend) rather than expressing both alleles equally (co-dominance) or one allele masking another (epistasis).
Information Booster:
In incomplete dominance the heterozygote phenotype is intermediate between the two homozygotes (e.g., RR = red, rr = white, Rr = pink).
Co-dominance would show both traits simultaneously (e.g., red and white patches), not a blend.
Incomplete dominance follows simple Mendelian inheritance at a single locus with two alleles.
Mirabilis jalapa (four o'clock) is a textbook example used to demonstrate this.
Pleiotropy refers to one gene affecting multiple phenotypic traits — unrelated to the blending seen here.
Additional Information (Incorrect Options):
(a) Co-dominance would produce both red and white expressed together (e.g., speckled), not a uniform pink.
(c) Epistasis involves one gene masking another’s expression — not a blending of two flower-colour alleles.
(d) Pleiotropy is about multiple effects of one gene, not intermediate phenotypes in heterozygotes.