In what case is the splitting of characters in the dihybrid cross of two diheterozygotes indicated by phenotypes?

With the crossbreeding of two diheterozygotes, the phenotype cleavage is: 9: 3: 3: 1

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.