Final answer:
A quantitative trait is influenced by multiple genetic and environmental factors, resulting in a range of phenotypes. Genetic components include the interaction of polygenes and alleles, while environmental factors can include diet and lifestyle, both of which can cause variations in expression of these traits.
Step-by-step explanation:
A quantitative trait is a measurable phenotype that depends on the cumulative actions of many genes and the environment. These traits show a continuous distribution of phenotypes, examples include height, skin color, and blood pressure. Genetic factors influencing quantitative traits include the number of genes involved (polygenes), the presence of various alleles contributing to the trait, and how these alleles interact with each other (gene interactions). Environmental factors such as diet, climate, and lifestyle also significantly impact these traits, leading to variations even among genetically similar organisms. Genetic factors such as mutations and natural selection can lead to changes in allele frequencies, thereby causing changes in the trait over time, while environmental factors can alter the way genes are expressed (phenotypic plasticity).