In a typical monohybrid, a cross with respect to a certain trait,...

In a typical monohybrid cross, the $F_2$ generation genotypic ratio is $1 : 2 : 1$ for homozygous dominant, heterozygous, and homozygous recessive respectively.

The proportion of homozygous plants (both dominant and recessive) is $\dfrac{1 + 1}{4} = \dfrac{1}{2}$.

The proportion of heterozygous plants is $\dfrac{2}{4} = \dfrac{1}{2}$.

Given the total number of plants in the $F_2$ generation is $120$.

Number of homozygous plants = $\dfrac{1}{2} \times 120 = 60$.

Number of heterozygous plants = $\dfrac{1}{2} \times 120 = 60$.

Answer: 60 and 60.