Final answer:
The cross (X) representing the probability of the spinner landing on Yellow would be placed at 0.75 on a probability scale, since the Punnett square indicates a 75% chance for yellow phenotype offspring. For a true-breeding cross between green and yellow seeds, all F1 offspring would be yellow, due to yellow being the dominant trait.
Step-by-step explanation:
The probability that the spinner will land on Yellow can be found using the information about the genetic cross provided. Given that the dominant allele Y results in a yellow phenotype and using the Punnett square, we can deduce the probabilities of the F2 offspring. Each time the spinner is spun, there's a 75% probability that the offspring will be yellow, since three out of the four squares in the Punnett square result in a yellow phenotype (YY, Yy, and yY). Therefore, if this proportion were translated onto a probability scale with 0 representing impossibility and 1 representing certainty, the cross (X) representing the event of landing on yellow would be placed at 0.75 on this scale.
For the seventh question, when true-breeding parents with green seeds and yellow seeds are crossed, and knowing that yellow seed color is dominant over green, all of the F1 offspring would have yellow seeds. This is because all of them would receive at least one Y allele from the yellow-seeded (YY) parent, resulting in a phenotype of yellow seeds for the offspring. Hence, the correct answer is 100 percent yellow seeds.