In which situation can organisms from a common ancestor develop large differences?

Correct answer: When they live in different environments for a long time

Descendants of a common ancestor may begin with similar inherited features, but separate environments expose them to different conditions and selection pressures. Heritable variations that are useful in one environment may be less useful in another. Repeated selection over many generations can therefore produce divergent adaptations, especially when populations are isolated and do not exchange genes freely. Option A is correct. Exact sameness, absence of variation, or absence of reproduction would prevent such evolutionary divergence rather than cause it.