When cold, the hair erector muscles

  1. contract so hairs trap a layer of air
  2. widen the arterioles
  3. release sweat
  4. relax so hairs lie flat
Answer

A) contract so hairs trap a layer of air

Trapped air insulates. O Level Biology · Topic 14 Coordination and Control · 14.5 Temperature control

Biology MCQ · More O Level Biology: Coordination and Control MCQs · Practise