What are the choices? But Carbohydrates are the main component of fruit and vegetables.
<span>The correct answer is b.0.5 to 1 micrometre thick.</span>
Usually, the respiratory membrane is about 0.6 micrometres thick. This membrane consists of the alveolar epithelial cells, the capillary endothelial cell, and basement membranes which are formed by the alveolar and capillary cells.
I think that this would be carbohydrates, I'm not completely sure though.
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