While working with the fruit fly Drosophila, a researcher discovers a single fly that is eyeless. He decides to mate this fly with a normal fly, and surprisingly, he found that all of the 65 offspring have eyes. What did he do wrong? What could explain these results? Is there another experiment/cross he could make to produce flies expressing the eyeless allele?

the two answers are a, the population of birds with large beaks will increase on the island, and c, the trait for large beaks will be passed on to future generations through natural selection. the reason for that is because if the birds that have beaks developed for eating small seeds lose all of their food, they will go hungry and eventually starve because they physically cannot eat the large seeds, therefore making the population of large beaked birds higher. also, if the trait of large beaks are dominant on the island over small beaks, then over time the large beaked birds will reproduce more and more, while the smaller beaked birds will reproduce less and less because they can't survive with the food provided. that leads to the trait of small beaks disappearing and the trait of large beaks taking over the island.