(N/A) Mendel's Law of Dominance states that in a heterozygous condition,the dominant allele expresses its phenotype,while the recessive allele remains masked. The recessive allele is not lost but remains hidden in the $F_{1}$ generation and reappears in the $F_{2}$ generation.
For example,when pea plants with round seeds $(RR)$ are crossed with plants with wrinkled seeds $(rr)$,all seeds in the $F_{1}$ generation are found to be round $(Rr)$. This demonstrates that the round trait is dominant over the wrinkled trait.
When these $F_{1}$ round seeds $(Rr)$ are self-fertilized,both round and wrinkled seeds appear in the $F_{2}$ generation in a $3:1$ phenotypic ratio. This confirms that the recessive trait (wrinkled seeds) was present but suppressed in the $F_{1}$ generation and reappeared in the $F_{2}$ generation.