Which cells of our body cannot respire anaerobically?

Correct answer: (b) Brain cells

Explanation

Brain cells (neurons) need a constant supply of oxygen and glucose. They depend on aerobic respiration and cannot meet their energy needs anaerobically, so a few minutes without oxygen can damage the brain permanently.

By contrast:

• mature red blood cells have no mitochondria, so they respire only anaerobically;
• muscle cells switch to anaerobic respiration during hard exercise, making lactic acid.