Statement-wise explanation

A. “Non-random mating between individuals closely related to each other would tend to promote a decrease in homozygosity at all loci.” – Incorrect

• Mating between relatives is inbreeding, which leads to increased homozygosity and decreased heterozygosity across the genome.

• So saying it “decreases homozygosity” is the opposite of what actually happens.

B. “Quantitative traits are typically influenced by environmental conditions to a greater extent than qualitative traits.” – Correct

• Quantitative traits (yield, height, biomass) are controlled by many genes and are usually highly environment-sensitive.

• Qualitative traits (simple Mendelian traits like flower color) are much less affected by environment.

• Thus B is a correct generalization.

C. “The over dominance theory for explanation of heterosis assumes that in a heterozygote, only one of the alleles plays a functional role.” – Incorrect

• Overdominance theory proposes that the heterozygote (A a) is superior because the combined effect of both different alleles is better than either homozygote (A A or a a).

• The statement given sounds like complete dominance, where one allele alone is functional; that is not overdominance.

• Therefore C misstates the theory and is incorrect.

D. “During domestication selected genes/traits show a decrease in diversity.” – Correct

• Domestication involves strong directional selection on specific loci (e.g., non‑shattering, large seeds).

• This typically causes selective sweeps, reducing variation around those selected genes compared with wild relatives.

• So D is correct.

Since only A and C are wrong, the combination of all incorrect statements is option (3) A and C only.