A mutant cucumber plant has flowers that fail to open when mature. Crosses can be done with this plant by manually opening and pollinating the flowers with pollen from another plant. When closed × open crosses were performed, all the F1 progeny were open. The F2 plants were 145 open and 59 closed. A cross of closed × F1 gave 81 open and 77 closed offspring. Describe the genetic basis of inheritance for this trait, including the evidence that led to your conclusions.