Question

which type of traits vary quantitatively due to the interaction of multiple genes?
○ polygenic
○ codominant
○ incomplete dominant
○ dominant

Explanation:

To solve this, we analyze each option:

• Polygenic traits: These are controlled by multiple genes (poly = many) and show quantitative variation (e.g., height, skin color). The interaction of multiple genes leads to a range of phenotypes.
• Codominant traits: Both alleles in a heterozygote are fully expressed (e.g., AB blood type), not related to multiple genes for quantitative variation.
• Incomplete dominant traits: The heterozygote has a phenotype intermediate between the two homozygotes (e.g., pink flowers from red and white), controlled by one gene with two alleles, not multiple genes.
• Dominant traits: A dominant allele masks the recessive one in a heterozygote (e.g., brown eyes over blue), usually controlled by one gene, not multiple genes for quantitative variation.

So, polygenic traits are those that vary quantitatively due to multiple gene interactions.

Answer:

A. polygenic