Dolly was the first mammal cloned.

• A. Dolly was the first mammal cloned by embryo splitting.
• B. Dolly was the first mammal cloned using somatic cell nuclear transfer.
• C. Dolly was the first mammal cloned via natural reproduction.
• D. Dolly was the first mammal cloned by genetic modification.

Answer: (B)

Cloning Dolly demonstrates somatic cell nuclear transfer. In this method, the nucleus from an adult somatic (body) cell is inserted into an egg cell that has had its own nucleus removed. The egg is then activated to begin development and is implanted to grow into an animal. Dolly was the first mammal cloned using this technique, showing that an adult cell’s genetic material can be reprogrammed to create a whole organism that is genetically identical to the donor.

Embryo splitting, by contrast, starts from an early embryo and divides it to form twins or more copies, not from an adult cell nucleus. Natural reproduction involves mating and fertilization, not cloning. Genetic modification involves directly altering genes, whereas Dolly’s genome was copied from the donor cell, not edited.