Mendel's monohybrid F2 ratio is:

In his experiments, Gregor Mendel performed a monohybrid cross, which studies the inheritance of a single trait (e.g., stem height). 1. **Parental Generation ($P$):** Mendel crossed pure-breeding plants with contrasting traits, such as tall ($TT$) and dwarf ($tt$). 2. **$F_1$ Generation:** All offspring were hybrids ($Tt$). Due to the Law of Dominance, all appeared tall. 3. **$F_2$ Generation:** Mendel self-pollinated the $F_1$ plants ($Tt \times Tt$). Using a Punnett square, the offspring genotypes are: - $1$ Homozygous Dominant ($TT$) - $2$ Heterozygous ($Tt$) - $1$ Homozygous Recessive ($tt$) 4. **Phenotype vs. Genotype:** - The **genotypic ratio** is $1 : 2 : 1$. - The **phenotypic ratio** (the physical appearance) is $3 : 1$, as both $TT$ and $Tt$ look tall while only $tt$ looks dwarf. By default, 'Mendel's monohybrid ratio' refers to the phenotypic ratio observed in the $F_2$ generation, which is $3 : 1$.