Question

If a plant is heterozygous for tallness, the F2 generation has both tall and dwarf plants. This proves the principle of
A. Dominance
B. Segregation
C. Independent assortment
D. Incomplete dominance

Answer 1

Hint: These Mendel’s law is universally accepted and has no exceptions and states that one allele from each parent combines to form the resulting genotype in the offspring.

Complete answer: According to the law of dominance, a trait is represented by two contrasting factors of a gene known as alleles in a heterozygous individual; in such a condition only, the dominant trait is expressed as the dominant allele masks the expression of the recessive allele, regardless of the presence of both factors, within a heterozygous individual. It doesn't tell about the reappearance of the missing trait in the F2 generation.

The law of segregation explains the fact that the two factors responsible for expressing the two contrasting traits, are always present together in a heterozygous individual; they don't get mixed and are ultimately separated during the formation of gametes.
Thus, each gamete finally receives one allele for a trait, and two kinds of gametes are formed; and hence, the given case proves the law of segregation.

So, the correct answer is option B. Segregation.

Note: The law of segregation is a universal law, and there are no exceptions for this law. The law of dominance on the other hand has certain exceptions.
The flowers of the plant Mirabilis jalapa exhibit incomplete dominance and show a mix of both the dominant (red) and recessive (white) flower color i.e. pink.