If tall stem is dominant and dwarf stem is recessive, what will the first generation be when a pure tall plant is crossed with a dwarf plant?
Answer and explanation
Correct answer: All heterozygous tall
Use T for the dominant tall allele and t for the recessive dwarf allele. A pure tall plant has genotype TT, while a dwarf plant must be tt. The cross TT × tt gives only Tt offspring because the first parent can provide only T and the second can provide only t. Every F1 plant is therefore heterozygous and phenotypically tall. A and C incorrectly predict dwarf offspring, while D confuses heterozygous Tt with homozygous TT.
Frequently asked questions
What is the correct answer to this question?
All heterozygous tall
Why is this the correct answer?
Use T for the dominant tall allele and t for the recessive dwarf allele. A pure tall plant has genotype TT, while a dwarf plant must be tt. The cross TT × tt gives only Tt offspring because the first parent can provide only T and the second can provide only t. Every F1 plant is therefore heterozygous and phenotypically tall. A and C incorrectly predict dwarf offspring, while D confuses heterozygous Tt with homozygous TT.
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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