Final answer:
Carbohydrates are organic compounds made of carbon, hydrogen, and oxygen in a 1:2:1 ratio, and are essential to human functioning as one of the four major classes of biochemical compounds.
Step-by-step explanation:
The group of organic compounds containing carbon, hydrogen, and oxygen in a near 1:2:1 ratio is defined as a carbohydrate. Carbohydrates are one of the four major classes of biochemical compounds, alongside lipids, proteins, and nucleic acids. These compounds are essential to human functioning and are organic because they contain both carbon and hydrogen. Carbohydrates typically are formed through covalent bonds between carbon, hydrogen, and oxygen atoms. The carbon atoms in carbohydrates, as in all organic compounds, share electrons via covalent bonds in accordance with the octet rule, which is a fundamental aspect of the chemistry of carbon.