Some isotopes, however, decay slowly, and several of these are used as geologic clocks. Dating rocks by these radioactive timekeepers is simple in theory, but the laboratory procedures are complex. <span>All methods rely on the fact that certain elements (particularly uranium and potassium) contain a number of different isotopes whose half-life is exactly known and therefore the relative concentrations of these isotopes within a rock or mineral can measure the age.</span>
Answer:
The correct answer is option D. "lipid".
Explanation:
Lipids, known also as fats or oils, are organic compounds that are insoluble in water and are made up of carbon, hydrogen, and oxygen. The formula of this question shows a biomolecule that is made up of this three atoms, and even though carbohydrate are made up of this three atoms as well, we can determine that it belongs to a lipid because it contains many more hydrogen atoms than oxygen atoms. Other characteristic of lipids is their long chains of carbon and hydrogen atoms, which are represented by the lines shown in blue. I attached the missing formula.