What are carbohydrates primarily composed of?

Carbohydrates are primarily composed of carbon, hydrogen, and oxygen, typically in a ratio that approximates 1:2:1. This means that for every carbon atom, there are roughly two hydrogen atoms and one oxygen atom present. The basic molecular formula for many carbohydrates (like glucose) can be expressed as Cn(H2O)n, which clearly demonstrates this ratio.

Carbohydrates include simple sugars like glucose and fructose, as well as complex carbohydrates such as starch and cellulose. The presence of oxygen is crucial, as it not only plays a role in the structure of these molecules but also in their functionality and energy storage capacity. Understanding this composition is fundamental to studying biological processes, as carbohydrates often serve as primary energy sources in living organisms.

The other options include elements that are not typically found in carbohydrates. For instance, nitrogen is not a primary component of carbohydrates, while stating that carbohydrates consist of only carbon and hydrogen or only hydrogen and oxygen misrepresents their molecular makeup.