Normally organisms undergo _____ to make usable energy from glucose in the presence of oxygen. However, ____ allows some organisms to generate energy in areas where there is no oxygen.

1. Anaerobic respiration, Aerobic Respiration
2. Anaerobic Respiration, Photorespiration
3. Photosynthesis, Glycolysis
4. Aerobic Respiration, Anaerobic Respiration