The energy yield in terms of ATP is higher in aerobic

The energy yield in terms of ATP is higher in aerobic respiration than during anaerobic respiration.
Why is there anaerobic respiration even in organisms that live in aerobic condition like human beings and angiosperms?

The anaerobic respiration occurs even in organisms that live in aerobic condition like human beings and angiosperms under conditions of oxygen scarcity that happens in the muscle tissue.
Under intense use, muscles demand too much energy (ATP) and consume much more oxygen to produce that energy.
This high consumption leads to oxygen scarcity and the muscle cells begin to make lactic acid by anaerobic respiration trying to fulfill their energetic needs. Similarly, yeast cells under deficient conditions carry out anaerobic respiration.