Two yellow-flowered hybrid plants each carrying a recessive factor for flowers with green colour were crossed. Which of the following ratios shows the corre...

In this scenario, both hybrid plants have a recessive factor for green flower color, which means they both have the genotype "yy". When these two plants are crossed, the Punnett square for the F1 generation will result in all offspring having the genotype "Yy" (yellow flower color). However, since the "Y" allele is dominant, they will all exhibit the yellow flower color phenotype. If two of these F1 offspring are crossed, the Punnett square for the F2 generation will result in a ratio of 3 yellow-flowered plants to 1 green-flowered plant. This is because both parents have a genotype of "Yy", meaning they each have a 50% chance of passing on the dominant "Y" allele or the recessive "y" allele to their offspring. The only way for a plant to have green flowers is to inherit two copies of the recessive "y" allele, which occurs with a probability of 1 in 4 or 25%. Therefore, the correct ratio is 1 in 4. So, the correct answer is "1 in 4".