Based on the description provided, the molecules in the image are likely to be monosaccharides, which are the building blocks of carbohydrates. Therefore, the option that best describes these molecules is:
They are all monosaccharides that form carbohydrates.
If the image contained structures resembling fatty acids rather than sugars, the appropriate answer would differ. However, without seeing the actual image, this is the most logical conclusion based on the context.