The phenotype ratio of 9: 3: 3: 1 obtained by crossing two digeterozygotes illustrates

Law of Independent Inheritance:
When two homozygous individuals are crossed that differ from each other in two (or more) pairs of alternative characters, genes and their corresponding characters are inherited independently of each other and combined in all possible combinations. The first generation after crossing possessed a dominant phenotype in all respects. In the second generation, phenotypes were split according to the formula 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.