Scientists carry out two adult-cell cloning procedures. In each procedure, the egg nucleus is removed before a body-cell nucleus is inserted. The resulting embryos are stimulated to divide and are placed in host mothers.
| Procedure | Egg donor | Body-cell nucleus donor | Host mother |
|---|---|---|---|
| P | Animal X | Animal Y | Animal Z |
| Q | Animal Z | Animal Y | Animal X |
The two young animals later have different body masses. No mutations have occurred.
Which interpretation correctly identifies their nuclear DNA and a possible cause of the mass difference?
P matches X and Q matches Z; their environments may have produced the different body masses.
P and Q both match Y; their environments must have changed the inherited nuclear DNA sequences.
P and Q both match Y; their environments may have produced the different body masses.
P matches Z and Q matches X; their environments must have changed the inherited nuclear DNA sequences.
44 exam-style questions on AQA GCSE Biology 6.2 Variation and evolution, covering 6.2.1 Variation, 6.2.2 Evolution, 6.2.3 Selective breeding, 6.2.4 Genetic engineering, and 6.2.5 Cloning. Each one has a worked solution and a mark scheme showing where the marks go.