All natural substances contain which element?

All natural substances, especially those that form the basis of living organisms and organic compounds, contain carbon. Carbon is often referred to as the building block of life because it has the unique ability to form stable bonds with many elements, including itself. This capability allows for the formation of complex molecules, such as proteins, nucleic acids, carbohydrates, and lipids, which are essential for life.

The presence of carbon in all natural substances is a fundamental concept in chemistry that underpins organic chemistry, the study of carbon-containing compounds. While hydrogen, nitrogen, and oxygen are also important elements found in many substances, they do not universally exist in all natural substances in the same way carbon does. For instance, some simple inorganic compounds may lack carbon but still contain hydrogen, nitrogen, or oxygen. Thus, while other elements are crucial for various biological processes and compounds, carbon's prevalence in all natural substances makes it the correct answer to the question.