السؤال 108

Natural selection is often described as acting on variation. Where does the variation it acts on come from?

Natural selection produces it as the conditions change
From mutation and from the new allele combinations of sexual reproductionالإجابة الصحيحة
From the efforts individuals make during their lives
It appears only in the offspring of the individuals that survive to breed

الشرح

The differences between individuals are in place before any selection happens: chance changes to DNA supply versions of genes that were not there before, and sexual reproduction deals the existing versions into a fresh combination for every offspring. Selection then removes some individuals and favours others, which lets it sort what exists but never invent it.

الشرح

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