The energy yield in terms of $ATP$ is higher in aerobic respiration than during anaerobic respiration. Why does anaerobic respiration occur even in organisms that live in aerobic conditions,such as human beings and angiosperms?

(N/A) Although aerobic respiration is more efficient in producing $ATP$,anaerobic respiration serves as a vital survival mechanism under specific physiological conditions.
$1$. In human beings: During intense physical exercise,the demand for $ATP$ in muscle cells increases rapidly. The rate of oxygen supply via the circulatory system may become insufficient to meet this high demand. In such cases,muscle cells temporarily switch to anaerobic respiration (lactic acid fermentation) to generate $ATP$ quickly,allowing the muscles to continue functioning despite the oxygen deficit.
$2$. In angiosperms (plants): Under conditions like waterlogging or soil compaction,roots may experience oxygen deficiency (hypoxia). To survive these temporary anaerobic conditions,plant cells can perform anaerobic respiration (alcoholic fermentation) to maintain basic metabolic processes until oxygen levels are restored.