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Many students who study using our platform have reported that a large number of the practice questions here are very similar to those that appear in real exams. View Courses
Many students who study using our platform have reported that a large number of the practice questions here are very similar to those that appear in real exams. View Courses
A plant with the genotype Tt (where T = tall, t = short) is crossed with another Tt plant. According to Mendelian genetics, what percentage of the offspring are expected to be short?
Correct Answer: A. 25%.
A Tt × Tt cross produces genotypes TT, Tt, Tt, and tt in a 1:2:1 ratio. Only tt results in short plants, representing 1 out of 4 outcomes (25%). This follows Mendel’s law of segregation, where alleles separate during gamete formation, allowing predictable inheritance patterns. The dominance of T ensures that heterozygous Tt plants are tall, leaving only the homozygous recessive tt expressing the short phenotype.
Why Other Options are Incorrect:
B. 50% would mean half of the offspring are short, but only 25% (tt) express the recessive trait. The Tt offspring are tall because the dominant allele masks the recessive one.
C. 75% confuses tall with short; indeed, 75% are tall (TT and Tt), not short. This option reverses phenotype proportions.
D. 100% implies all offspring are short, which is genetically impossible from heterozygous parents since dominant alleles guarantee some tall offspring.
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