What defines an organ in biological terms?

An organ is defined in biological terms as a structure composed of several types of tissues that work together to perform specific functions within an organism. This means that an organ is more complex than just a single type of tissue or a collection of cells.

For example, in the human body, the heart is an organ made up of muscle tissue that contracts to pump blood, connective tissue that supports the heart structure, and nervous tissue that helps regulate heartbeats. This multi-tissue composition allows the heart to perform its critical function efficiently.

In contrast, a type of cellular component might refer to organelles within a single cell, and a single type of tissue is just one form of biological tissue without the integration seen in organs. A mere collection of cells lacks the organized function and structural complexity necessary to be classified as an organ. Therefore, the definition of an organ as a structure composed of several tissues underscores its role in the overall functioning of an organism.