Answer:
Due to mutation.
Step-by-step explanation:
The genotype and phenotype of circled offspring is different from the non-circled offspring because it has different genetic makeup, that is responsible for its different color. The change in the circled offspring's genotype was caused by a mutation. Mutation is a change that occurs in the DNA sequence, or genetic makeup of an organism due to mistakes when the DNA is copied or environmental factors such as UV light and smoke etc.