Why are saturated fats referred to as "saturated"?

Saturated fats are referred to as "saturated" because they are rich in hydrogen atoms. In these fats, every carbon atom in the fatty acid chain is bonded to as many hydrogen atoms as possible, meaning there are no double bonds between the carbon atoms. This leads to a fatty acid structure that is "saturated" with hydrogen. The presence of single bonds between the carbon atoms means that the fatty acid chains can pack closely together, which contributes to their solid state at room temperature.

The other options do not accurately describe saturated fats. For instance, the presence of a phosphate group pertains to phospholipids, not saturated fats. Multiple double bonds are characteristic of polyunsaturated fats, while a lack of carbon chain double bonds aligns with the structure of saturated fats but does not address the reason behind the term "saturated." Therefore, the richness in hydrogen atoms is what fundamentally defines saturated fats, reflecting their chemical structure.