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Why is fructose classified as a ketohexose?

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Tall, dense stalks of sugarcane grow on both sides of a narrow path, with green leaves arching overhead and sunlight illuminating the plants. — sugar Lines of sugarcane before harvest.

Fructose is classified as a ketohexose based on its structural composition and the presence of a specific functional group.1

The term "hexose" indicates that the monosaccharide contains six carbon atoms. The prefix "keto-" denotes that the molecule contains a keto group as its chemically reactive group, typically located at the second carbon position within the chain. Unlike glucose, which is an aldohexose because it contains an aldehyde group, fructose is categorized as a ketohexose due to this distinct structural arrangement of its atoms.1