Question

Where does diffusion occur in the respiratory system?

Answer 1

Lungs are located on both lateral sides of the breastbone in the chest cavity. To be precise, lungs are found on the right and to the left side. Lungs are partitioned into five lobes mainly- the right lung has three lobes- upper, middle and lower. Middle lobe is absent here. The function lungs possess is filling air and exerting carbon dioxide.

Complete answer-
Lungs are spongy organs filled with air present at the thorax on the right side. Lungs are present in almost every animal including humans, tetrapods, few fish and some snails. It is the major organ for respiration. Mostly in mammals the lungs are located at the backbone towards both the sides of the heart. Lung function Is to- extract oxygen which comes via nose to lungs and transfer it directly into the bloodstream and release carbon dioxide.
This is the gaseous exchange lung does every time when it extracts air from the atmosphere. Respiration is processed by different muscular systems in different species. In earlier dates, tetrapods have lungs which are air driven by pharyngeal muscles and buccal pumping. The same mechanism was also seen in amphibians too.
But in humans, the respiration muscle is a diaphragm. The lungs make an airflow with vocal sounds which also include human speech possible. The lungs weigh $1.3$kilograms from which the right lobe is heavier. Lungs have parts like- alveoli, bronchioles, sacs and ducts.
Alveoli is the place where diffusion is likely to take place. It is the sudden movement of influx and outflux of gases without any effort from the body. Alveoli and capillaries are always put into action inside the lungs.

Note:
Lungs filled the air approximately $2,400$ kilometers. From which $300 - 500$ million are filled in alveoli. Each lung is wrapped within a sac called pleural sac containing pleural fluid, which allows breathing from inner to outer walls to slide from each other. They contain a unique blood supply by receiving deoxygenated blood from the heart and oxygenated from the purpose of receiving oxygen.