Under which condition will a recessive trait appear externally?
Answer and explanation
Correct answer: When both gene forms are recessive
The governing concept is dominance and recessiveness. A dominant allele can mask the expression of a recessive allele in a heterozygous condition, such as Aa. A recessive phenotype appears only when both alleles are recessive, represented by aa, because no dominant allele is present to mask it. Therefore option A is correct; option B gives a dominant phenotype, while C also expresses dominance and D is biologically impossible.
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What is the correct answer to this question?
When both gene forms are recessive
Why is this the correct answer?
The governing concept is dominance and recessiveness. A dominant allele can mask the expression of a recessive allele in a heterozygous condition, such as Aa. A recessive phenotype appears only when both alleles are recessive, represented by aa, because no dominant allele is present to mask it. Therefore option A is correct; option B gives a dominant phenotype, while C also expresses dominance and D is biologically impossible.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: World of Living. Topic: Heredity and Evolution.
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