Question

in the 1800s gregor mendel crossed pea plants that had purple flowers with pea plants that had white flowers. he had expected to see a mixture of colors in the offspring but instead all the offspring had purple flowers. which current understanding of the patterns of inheritance is best supported by mendel’s observations?
a. the two alleles of a gene are fully expressed in a heterozygote.
b. a mutated gene in a somatic cell cannot pass the trait to offspring.
c. genes located on the sex chromosomes show sex - linked inheritance.
d. some genes are expressed as either dominant or recessive in offspring.

Explanation:

Mendel's experiment with pea plants showed that when purple - flowered and white - flowered plants were crossed, all offspring had purple flowers. This is because the purple flower allele is dominant and the white flower allele is recessive. Option A is incorrect as it describes codominance, not what happened here. Option B is about somatic mutations, which is not related to this inheritance pattern. Option C is about sex - linked inheritance, and pea plants don't have sex chromosomes in the context of this simple inheritance. Option D correctly states that some genes (like the flower color gene in this case) are expressed as dominant (purple) or recessive (white) in offspring, which explains why all offspring showed the purple (dominant) trait.

Answer:

D. Some genes are expressed as either dominant or recessive in offspring.