A Level Biology Practice Exam 2025 – All-in-One Study Guide to Excel in Your A Levels!

An organ system is defined as a number of organs working together to perform a specific function. This concept is integral to understanding how complex biological processes are carried out within living organisms. Multiple organs collaborate within a system to achieve a common purpose, enhancing efficiency and specialization.

For instance, the digestive system includes various organs such as the stomach, intestines, and liver, all coordinated to process food and absorb nutrients. This collaboration is essential for the organism's survival and highlights how interdependent organ systems are, each contributing uniquely to the organism's overall function.

Other options imply definitions that do not fully encompass the idea of an organ system. A single organ performing multiple functions refers to the versatility of individual organs rather than a collection working in concert. An organized collection of tissues describes the building blocks of organs, while a taxonomic grouping of similar organs is more about classification rather than their functional interaction.