15. Примером приспособления животных к условиям природной зоны пустынь и полупустынь является

The most fitting adaptation for desert and semi-desert animals among the given options is the ability to tolerate low temperatures, as deserts can experience significant temperature drops at night. Option 4, nocturnal or crepuscular activity, is also a strong adaptation for avoiding extreme heat, but the question asks for an example of adaptation to the conditions of deserts and semi-deserts in general, which includes temperature fluctuations. Option 2 is more typical of tundra or temperate zones. Option 3 is irrelevant to desert environments. Therefore, the ability to withstand low temperatures is a key adaptation.