To determine the percentage of tall offspring from a cross between a heterozygous tall pea plant (Tt) and a homozygous recessive short pea plant (tt), we can use a Punnett square.
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The genotypes of the parents are:
- Heterozygous tall (Tt)
- Homozygous recessive short (tt)
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Set up the Punnett square:
| | T | t | |-------|-------|-------| | t | Tt | tt | | t | Tt | tt |
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The possible genotypes of the offspring are:
- Tt (tall)
- tt (short)
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From the Punnett square:
- 2 out of 4 offspring will be Tt (tall)
- 2 out of 4 offspring will be tt (short)
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This means that 50% of the offspring are expected to be tall plants.
Therefore, the answer is b 50%.