A tall pea plant of unknown genotype is crossed with a short plant. The 26 offspring are 12 tall and 14 short. What is the best conclusion?
Answer and explanation
Correct answer: B. The tall parent is heterozygous
- Step 1: A short plant is tt, so it gives only t gametes (a test cross).
- Step 2: Short offspring (tt) must have received t from the tall parent, so the tall parent is Tt.
- Step 3: The ratio near 1:1 matches Tt x tt.
Answer
the tall parent is heterozygous.
Why not the others: A homozygous tall parent would give all tall offspring; the short parent can only be tt; a 1:1 ratio is typical of inherited traits.
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