A purebred plant that has yellow flowers is crossed with a purebred plant that has white flowers. All the offspring have yellow flowers. Which conclusion about yellow flowers is supported by these results?

The purebred yellow plant has two copies of the yellow-color allele, and the purebred white plant has two copies of the white-color allele. Since every offspring has yellow flowers, the yellow allele masks the white allele in the offspring. This supports the conclusion that yellow flower color is dominant.

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