A research lab requires a supply of pure breeding freckled frogs (FF) for a cloning experiment. A lab assistant has a pet frog with freckles but it's uncertain if it is homozygous or heterozygous. A test-cross is called for! The pet frog is crossed with a homozygous recessive smooth (non-freckled) frog (ff). Half of the offspring are freckled frogs and half are smooth. What does this tell you? Explain by using the two possible Punnett squares.
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