In which body system would you find information on asthma?

Asthma is primarily a condition related to the lungs and airways, which fall under the respiratory system. This system is responsible for the processes of breathing, gas exchange, and maintaining proper oxygen levels in the body. Asthma is characterized by inflammation and narrowing of the airways, leading to difficulty in breathing, wheezing, and a feeling of tightness in the chest.

Understanding asthma requires knowledge of how the respiratory system functions, including the role of the bronchial tubes and the effects of various triggers that can exacerbate this condition, such as allergens, pollution, and respiratory infections. The other systems listed do not pertain to apnea in function or related disorders. Thus, the correct choice is firmly based on the direct association of asthma with the respiratory system.