What term describes structures formed by molecules combining together?

The term that describes structures formed by molecules combining together is organelles. Organelles are specialized structures within a cell that perform distinct functions, and they are made up of various combinations of molecules, including proteins, lipids, and nucleic acids.

For example, the nucleus, mitochondria, and endoplasmic reticulum are all types of organelles, each formed from complex molecular assemblies that enable them to carry out specific roles essential for the cell's life and function.

Cells, on the other hand, are the basic units of life that comprise organelles along with other components. Tissues consist of groups of similar cells working together to perform a particular function, which is a level of complexity beyond individual molecules. Atoms are the basic building blocks of matter and do not represent combined structures; instead, they are the individual units that make up molecules. Thus, organelles specifically encapsulate the concept of molecular combinations within a cellular context.