Question relating to human adaptations to cold environments: In a cold environment, humans use shivering as a method of keeping warm. Describe and explain the process of shivering.

DESCRIBE aspect of the question: Shivering describes the involuntary contractions our muscles make when our core temperature starts to drop below 37 degrees Celcius.
EXPLANATION: Actin and myosin filaments interact with each other during muscle contraction, with energy in the form of ATP being used to make and break bonds. Muscle contraction is inefficient and heat is produced as a by-product. Stored chemical energy is converted into heat energy as the muscles contract. This can increase heat production 5-fold.
Whilst explaining this to the student, I would also remind them of the respiration equation:
glucose + oxygen --> energy (ATP) + carbon dioxide + water
This energy can be used for cell activity, such as in muscle contraction.
A further point of interest would be that the efficiency of shivering is partially offset by enhanced convective heat loss to the environment that results from trembling. This may diminish its usefulness, especially where the surface-area-to-volume ratio of the person is large, as in children. This is possibly why babies do not shiver! Instead, they rely on brown fat thermogenesis.
This question would also familiarise the student with a key exam technique - how to answer a 'describe and explain' question - a definition, along with a subsequent explanation is key.