True or false. one character in peas that mendel studied was yellow versus green seeds. a cross between a homozygous yellow line (yy) and a homozygous green line (yy) will result in f1 plants that are heterozygous (yy) for this trait and produce yellow seeds.

True

Explanation:

Gregor Mendel worked with pea plant (Pisium sativum) and one of the genes he closely observed was the one coding for seed colour.

He crossed a yellow seeded pea plant (YY) with a green seeded one (yy). These parent plants are referred to as PUREBRED PARENTS. He realized that the resulting offsprings called F1 generation were all Yellow seeded, which is in accordance with Mendel's law of dominance and uniformity (expression of a dominant allele in a gene)

A significant observation was that the F1 offsprings were genetically mixed or heterozygous i.e. their genotype consisted of two different alleles (Yy).

This concept explained that, in a gene, an allele is capable of masking the expression of another. The allele that masks or is expressed is the DOMINANT allele while the allele being masked is called RECESSIVE allele.

In this case, the yellow seeded pea plant is dominant over the green seeded pea plant (recessive).

Mendel provided proof that an allele can be present but masked when he crossed two heterozygous F1 plants to produce F2 offsprings (3 yellow, 1 green).