18. Pentose(s)is (are): fructose ribose xylulose mannose deoxyribose

## Step 1<br />Pentose is a type of sugar that contains five carbon atoms. The options provided in the question are all types of sugars, but not all of them are pentoses.<br /><br />## Step 2<br />Fructose, xylulose, and mannose are hexoses, which means they contain six carbon atoms. Therefore, they are not pentoses.<br /><br />## Step 3<br />Ribose and deoxyribose, on the other hand, are pentoses. They contain five carbon atoms each.