Which biological structures give cells their structure and function?

The correct answer is organelles because they are specialized structures within cells that perform distinct functions necessary for the cell's life and operation. Organelles like the nucleus, mitochondria, ribosomes, and endoplasmic reticulum contribute to various processes, including energy production, protein synthesis, and genetic material management. The presence of these organelles allows cells to maintain their internal organization and carry out complex biological activities effectively.

While other components like proteins, RNA molecules, and cell membranes play vital roles in cellular function, they do not serve as the primary structural frameworks or functional units. Proteins, for instance, are often products of organelle activity, particularly ribosomes, and contribute to the cell's structural integrity and function but are not themselves the defining structures of the cell. RNA molecules are primarily involved in the transmission of genetic information and do not directly contribute to the physical structure. Cell membranes serve as barriers for the cell environment and facilitate communication but are not the internal structures that give the cell its functionality—that role is specifically fulfilled by organelles.