Since Mendel's time, types of inheritance that don't follow Mendel's rules have been discovered. Which of the following situations is NOT an exception to Mendel's rules? A) A phenotype in the offspring is intermediate between the two parental phenotypes. B) Phenotypes of the offspring show range of phenotypes rather that two distinct phenotypes. C) When doing a dihybrid cross between two heterozygous F₁ offspring, the ratio obtained is statistically different from the Mendelian ratio. D) When an individual with a heterozygous phenotype for a trait is crossed with an individual with a homozygous recessive phenotype, the ratio of phenotypes of the offspring is 1:1. E) Two or more gene pairs are involved in producing the phenotypes of a given trait.

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Option D describes a simple test cross, which is a basic Mendelian concept where an individual with an unknown genotype is crossed with a homozygous recessive individual. The resulting phenotypic ratio of 1:1 for dominant to recessive traits in the offspring is expected according to Mendel's laws when the unknown genotype is heterozygous.

Since Mendel's Time, Types of Inheritance That Don't Follow Mendel's