Assertion : Incomplete dominance is a deviation from law of dominance.

Reason : In incomplete dominance, F₁ generation did not resemble either of the two parents and was in between the two parents.

Assertion is true.  Incomplete dominance is a deviation from the law of dominance. In classical Mendelian genetics, the law of dominance states that when two homozygous parents with contrasting traits are crossed (one dominant and one recessive), all the F₁ offspring will exhibit the dominant trait. The recessive trait will only be observed in the F₂ generation when the F₁ individuals are crossed.

Reason is true. In incomplete dominance, the F₁ generation does not show the typical dominant and recessive phenotypes seen in classical Mendelian genetics. Instead, the F₁ individuals display an intermediate phenotype, which is a blending of the phenotypes of the two parents. This blending occurs because neither allele is completely dominant over the other, leading to an intermediate expression of the trait in the heterozygous offspring.

Both assertion and reason are true and reason is correct explanation of assertion.