The picture is a photomicrograph of a transverse section of a part of the gas exchange system. Which description matches the image?
- Aa thin inner layer of ciliated epithelial cells on top of a layer containing cartilage and supported by elastic fibres
- Ba very thin epithelial lining with walls containing elastic fibres, surrounded by many blood vessels
- Can inner layer of ciliated epithelial and goblet cells on top of elastic fibres and supported by an outer layer consisting of blocks of cartilage
- Dan inner layer of ciliated epithelial and goblet cells on top of loose tissue with mucous glands supported by an outer layer of cartilage