To find out whether a tall pea plant is homozygous or heterozygous, it should be crossed with
Correct answer: B. a dwarf plant
- A. another tall plant of unknown genotype
- B. a dwarf plant
- C. a known heterozygous tall plant
- D. itself only
Explanation
A test cross uses the homozygous recessive parent, here the dwarf, because such a parent contributes only recessive alleles and so the offspring show the unknown parent's contribution directly. All tall offspring mean the parent was homozygous, while about half dwarf offspring mean it was heterozygous. Crossing with another tall plant hides the answer, since a dominant allele from either parent masks the recessive.
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About Mendel's Laws of Inheritance
Mendelian inheritance explains how alleles separate into gametes and assort during reproduction, producing predictable genotype and phenotype ratios. Questions cover dominance, recessiveness, homozygous and heterozygous conditions, the laws of segregation and independent assortment, monohybrid and dihybrid crosses, test crosses and the limits caused by linked genes.
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