Assertion (A): Dolly was the first cloned mammal. Reason (R): Dolly was produced by in vitro fertilization.
✓ Correct answer: c) A is true but R is false
ExplanationCloning is the process of creating genetically identical copies of an organism, cell, or DNA sequence.It can be natural (as in identical twins) or artificial (like somatic cell nuclear transfer, used in Dolly the sheep).Assertion (A) is true: Dolly the sheep, born in 1996, was the first mammal successfully cloned from an adult somatic cell, making her a landmark achievement in biotechnology.Reason (R) is false: Dolly was not produced through in vitro fertilization (IVF), which involves the fusion of sperm and egg outside the body.She was created using somatic cell nuclear transfer (SCNT), a process in which the nucleus of a somatic cell (in Dolly’s case, a mammary gland cell) was transferred into an enucleated egg cell (an egg cell with its nucleus removed).The resulting cell was stimulated to divide and develop into an embryo, which was then implanted into a surrogate sheep for gestation.33
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