The organic molecule with a 1:2:1 ratio of carbon, hydrogen, and oxygen is carbohydrate.

Here's why:

* Carbohydrates are made up of carbon, hydrogen, and oxygen in a specific ratio. The general formula for carbohydrates is (CH₂O)n, where "n" represents the number of carbon atoms. This formula reflects the 1:2:1 ratio.

Let me know if you have any other questions!