一般是经由鳃呼吸。大部分硬骨鱼有鳔，这是源于消化管的憩室，司控制浮力或为辅助呼吸器官。
1·It is also produced when living organisms respire.
二氧化碳也可经由活体生物的呼吸作用而产生。
2·Sensitive varieties apprently respire mainly by the glycolysis pathway whereas resistant varieties depend more on the pentose phosphate pathway.
显然敏感品种的呼吸主要通过糖酵解途径，而抗性品种比较依赖戊糖磷酸途径。
3·Because I wish I can respire the natural fresh air during exercise, which is more health and benefit to my body.
因为我喜欢在运动的同时能呼吸到大自然的清新空气，这样更健康，更有益。
4·In this condition it is propitious to aerate and filter in the soil and respire in the roots, at the same time it meliorates roots growth environment.
在这种新型的节水措施下，有利于中层土壤的通透性和根系的呼吸，使根系的生长条件改善。