Why did the f1 offspring of mendel's classic pea plant crosses always look like one of the two parental varieties?

The F1 offspring of Mendel's classic pea plant crosses always looked like one of the two parental varieties because he crossed a homozygous dominant plant with a homozygous recessive plant so each plant received one recessive allele and one dominant allele. All of the plants looked like one plant because the dominant allele overshadowed the recessive allele