Given a text passage, come up with an appropriate title for it. The title should accurately represent what the main focus of the passage is. The title of a passage may be present in the first few sentences of the passage and/or be referred to multiple times in the passage. The title should be 1-5 words long.

A carbohydrate is a biological molecule consisting of carbon ( C ) , hydrogen ( H ) and oxygen ( O ) atoms , usually with a hydrogen -- oxygen atom ratio of 2 : 1 ( as in water ) ; in other words , with the empirical formula C ( H O ) ( where m could be different from n ) . This formula holds true for monosaccharides . Some exceptions exist ; for example , deoxyribose , a sugar component of DNA , has the empirical formula C H O. Carbohydrates are technically hydrates of carbon ; structurally it is more accurate to view them as polyhydroxy aldehydes and ketones .
Carbohydrate