Science — AI-generated practice question

During sudden activity, muscles work vigorously and need more energy. When oxygen supply is insufficient, glucose is broken down anaerobically, producing lactic acid. The accumulation of lactic acid in the muscle cells causes cramps — a painful sensation due to lack of proper oxygen supply during the sudden exertion.

Source: Chapter 6, Life Processes (related biochemistry of muscle activity)

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• The examiner expects the key terms: anaerobic respiration, lactic acid accumulation, and insufficient oxygen.
• Many students lose marks by only saying "lactic acid builds up" without explaining why (oxygen shortage during sudden activity).
• This concept links to Chapter 6 muscle action and energy release — keep the answer focused on the biochemical cause, not just the symptom.