Most human traits are determined by __________.

• A. a single gene
• B. multiple genes
• C. nutrition during infancy
• D. a single allele

Answer: (B)

Verified step by step guidance

1. Begin by understanding the concept of polygenic traits. These are traits that are influenced by multiple genes, rather than a single gene. This is a common occurrence in human genetics.
2. Consider examples of polygenic traits in humans, such as height, skin color, and eye color. These traits are the result of the combined effect of several genes, each contributing to the final phenotype.
3. Reflect on the role of alleles in genetics. An allele is a variant form of a gene, and while a single allele can influence a trait, complex traits often involve multiple alleles across different genes.
4. Evaluate the impact of environmental factors, such as nutrition during infancy, on human traits. While these factors can influence development, they do not determine genetic traits directly.
5. Conclude by recognizing that most human traits are determined by the interaction of multiple genes, making them polygenic. This complexity allows for a wide range of phenotypic variation among individuals.