Which idea is depicted by a cross in which the F₁ generation resembles both the parents?

If in a cross,  the  ${\mathrm{F}}_1$  generation individuals resemble both the parents. It is a case of codominance pattern of inheritance. In heterozygote, the phenotypic effect of both the alleles of a gene are fully and simultaneously expressed, e.g., AB blood group in man and roan coat colour in cattle are due to codominance of alleles.