As terrestrial organisms scale up in size, simple diffusion across their outer body surface becomes insufficient to meet metabolic demands. In insects, a specialized internal gas exchange system has evolved to overcome this challenge of size by delivering oxygen directly to active tissues.
Which of the following shows the correct sequence of structures that oxygen passes through as it diffuses from the atmosphere to the site of cellular respiration?
tracheae→spiracles→tracheoles→respiring cells\text{tracheae} \rightarrow \text{spiracles} \rightarrow \text{tracheoles} \rightarrow \text{respiring cells}tracheae→spiracles→tracheoles→respiring cells
spiracles→tracheae→tracheoles→respiring cells\text{spiracles} \rightarrow \text{tracheae} \rightarrow \text{tracheoles} \rightarrow \text{respiring cells}spiracles→tracheae→tracheoles→respiring cells
spiracles→tracheoles→tracheae→respiring cells\text{spiracles} \rightarrow \text{tracheoles} \rightarrow \text{tracheae} \rightarrow \text{respiring cells}spiracles→tracheoles→tracheae→respiring cells
spiracles→tracheae→bronchioles→respiring cells\text{spiracles} \rightarrow \text{tracheae} \rightarrow \text{bronchioles} \rightarrow \text{respiring cells}spiracles→tracheae→bronchioles→respiring cells