Question

gregor mendel studied pea plants and identified purple flowers as a dominant trait over white flowers. to confirm his results, a scientist crossed two pea plants having purple flowers and discovered that roughly 25% of their offspring had white flowers. what is the most appropriate explanation for these results? a mutation occurred, causing 25% of the pea - plant offspring to have the recessive white - flower version of the gene. the soil or another environmental condition caused 25% of the pea - plant offspring to have white flowers. the pea plants with purple flowers each had one dominant and one recessive gene for flower color. a result of white - flower offspring from purple parent flowers is impossible and was due to experimental error.

Explanation:

According to Mendelian genetics, when two heterozygous individuals (plants with one dominant and one recessive gene for a trait) are crossed, the expected ratio of dominant - to - recessive phenotypes in the offspring is 3:1. Here, purple is dominant and white is recessive, and approximately 25% white - flowered offspring (1 in 4) are consistent with the cross of two heterozygous purple - flowered plants. Mutations are rare and not the most likely explanation for this common genetic ratio. Environmental factors usually do not change the genetic - based flower color trait in this way. And it is not impossible to get white - flowered offspring from purple - flowered parents if the parents are heterozygous.

Answer:

C. The pea plants with purple flowers each had one dominant and one recessive gene for flower color.