Understand that organic compounds are primarily defined by the presence of carbon atoms (C) bonded to other elements.
Recall that the most common element bonded to carbon in organic compounds is hydrogen (H), forming hydrocarbons and many other organic molecules.
Recognize that while elements like phosphorus, sulfur, and chlorine can be present in some organic compounds, they are not as universally common as hydrogen.
Therefore, the element that most organic compounds contain along with carbon is hydrogen.
Summarize that the typical composition of organic compounds is carbon and hydrogen, often with other elements, but hydrogen is the most fundamental partner to carbon.