8. Match the correct word with the following definition: cavities of the skull filled with air in and around the nasal region, help to lighten the bones of the skull Cilia External Respiration Larynx Sinuses

## Step 1<br />The problem is asking us to identify the correct term that matches the given definition. The definition describes "cavities of the skull filled with air in and around the nasal region, help to lighten the bones of the skull". <br /><br />## Step 2<br />We need to match this definition with the given options: Cilia, External Respiration, Larynx, and Sinuses.<br /><br />## Step 3<br />Upon examining the options, we can see that the term "Sinuses" matches the given definition. Sinuses are air-filled cavities located within the bones of the skull and face. They are connected to the nasal cavity and help to lighten the weight of the skull, improve voice resonance, produce mucus, and contribute to the sense of smell.