Step 1 : Introduction to the question "2. A group of organic molecules that we encounter regularly in our food is carbohydrates. Which of these elements is NOT found in a carbohydrate molecule?"
...1. Carbon 2. Oxygen 3. Hydrogen 4. Nitrogen Carbohydrates contain carbon, hydrogen and oxygen. They usually have twice as many hydrogen atoms as carbon atoms, the same ratio as is found in water, which is the source of the -hydrate part of their name. For a chemist, carbohydrates include not only the large molecules that dieticians usually mean when they use the term, but also small molecules such as the monosaccharide glucose (blood sugar) and the disaccharide sucrose (table sugar).