Question

question 1-21
a cross between two pea plants, each heterozygous for both tall height and round seeds, produces the following results: some plants are tall with round seeds, some plants are tall with wrinkled seeds, some plan
explains why this occurs?

codominance of traits

polygenic expression of traits

incomplete dominance of alleles

independent assortment of alleles

Explanation:

When two pea plants heterozygous for two traits (tall height and round seeds) are crossed, the different combinations of traits in the offspring (tall - round, tall - wrinkled, etc.) occur due to the independent assortment of alleles. During meiosis, the alleles of different genes (for height and seed shape here) assort independently into gametes. This means that the allele for tall (or short) can combine with the allele for round (or wrinkled) in different ways, leading to various phenotypic combinations. Codominance is when both alleles are expressed equally (not the case here), polygenic expression involves multiple genes for one trait (here we have two separate traits), and incomplete dominance is when a blend of traits occurs (also not the case here). So the correct reason is independent assortment of alleles.

Answer:

D. independent assortment of alleles (assuming the option with "independent assortment of alleles" is option D, adjust the identifier as per the actual question's option numbering. If the original question's correct option is labeled as, say, the fourth option with text "independent assortment of alleles", then the answer would be like "4. independent assortment of alleles" or with the correct letter/number identifier as per the question's options.)