Question

a purebred purple flowering plant is crossed with a purebred white flowering plant, and they produce offspring that have purple flowers. which is the trait for purple flowers? dominant recessive codominant blended

Explanation:

According to Mendelian genetics, when a purebred (homozygous) purple - flowering plant is crossed with a purebred (homozygous) white - flowering plant, if all the offspring show the purple - flower trait, the purple - flower trait is dominant. A dominant trait is one that is expressed in the heterozygous condition (when an organism has one allele for the dominant trait and one for the recessive trait). In this case, let's assume the allele for purple flowers is \(P\) (dominant) and for white flowers is \(p\) (recessive). The purebred purple - flowered plant has a genotype \(PP\) and the purebred white - flowered plant has a genotype \(pp\). Their cross \(PP\times pp\) gives all offspring with genotype \(Pp\). Since all \(Pp\) offspring show the purple - flower phenotype, purple is dominant. Recessive traits are only expressed when an organism is homozygous for the recessive allele (e.g., \(pp\) would show the white - flower trait if white were recessive, but in our case, the offspring with \(Pp\) show purple). Codominant traits would result in both traits being expressed simultaneously (e.g., if flowers had both purple and white patches). Blended traits would result in an intermediate phenotype (e.g., light purple flowers if purple and white blended), but here we have all purple flowers.

Answer:

dominant