The law of splitting signs or Mendel’s second law.

Law: when crossing a pair of hybrids of the first generation (Aa x Aa), with dominant (A) and one recessive (a) traits, their offspring is split according to the genotype in a ratio of 1: 2: 1, but according to the phenotype, the splitting will be 3: 1. The basis of this law is the regular actions of a pair of homologous chromosomes, providing two types of gametes (A, a) in the first generation hybrids. The result is individuals of three genotypes of hybrids of the second generation: AA, Aa, aa in a ratio of 1 AA: 2 Aa: 1 aa.