Which of these is a mechanism of temperature regulation rather than an adaptive feature of a mammal?

1. An adaptive feature is a structure the animal permanently possesses. 2. A mechanism is a physiological response switched on and off as conditions change. 3. Fat layers, fur and large ears are structures, so they are adaptive features. 4. Vasodilation is a response — vessels widen to lose heat, then narrow again. 5. Listing vasodilation, vasoconstriction, sweating and hair erector muscles when asked for adaptive features was the recorded error that cost most of the marks. _Source: NECTA ACSEE 2023 Biology 133/2, Question 2: Regulation (Homeostasis)_