In aerobic respiration, pyruvate breaks down into carbon dioxide and water. In anaerobic respiration (in human muscle cells), pyruvate converts into lactic acid.
The examiner wants only the products, not the full process. Remember: in humans, anaerobic breakdown gives lactic acid (not ethanol + CO₂, which is yeast). State one product per condition clearly.
Source: Chapter 5, Section 5.3 Respiration