A researcher grew genetically identical vegetative cuttings taken from a single Hydrangea macrophylla shrub under two contrasting soil conditions. Plants cultivated in acidic soil with bioavailable aluminum developed blue flowers, whereas those grown in neutral-to-alkaline soil developed pink flowers. When new cuttings taken from the pink-flowered plants were rooted and cultivated in the acidic soil, they developed blue flowers. Which of the following conclusions is best supported by these observations?

A) Soil pH caused directed, heritable mutations in the structural genes encoding floral pigments.

B) Environmental factors can modify phenotypic expression without altering the organism's genome.

C) Floral pigmentation is determined by codominant nuclear alleles that segregate during vegetative propagation.

D) The acidic environment induced irreversible epigenetic silencing of all pink pigment alleles.

Environmental effects on phenotype Transitional Reasoning Practice

Biology · Heredity · Biology · Non-Mendelian Genetics

1 Biology practice questions on Environmental effects on phenotype. Questions that build towards applied reasoning.

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Heredity · Biology

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