Which of the following structure types is composed of specialized cells working together?

The concept of tissue is defined as a grouping of specialized cells that work together to perform a specific function. Tissues are essential building blocks in multicellular organisms, where they combine to form organs, which in turn contribute to the overall function of an organism.

In the context of biology, tissues can be classified into different types—such as epithelial, connective, muscle, and nervous tissues—each serving distinct roles in the body. For example, muscle tissue specializes in contraction and movement, while nervous tissue is involved in signal transmission.

Other options such as organism, molecule, and cell do not specifically refer to a collection of specialized cells working together for a common purpose. An organism is a complete living entity that can be formed from many tissues, but it is not a type itself. A single cell is the basic structural and functional unit of life, and a molecule is a chemical structure made up of atoms. These do not encapsulate the concept of specialized cells working together as a tissue does. Thus, the definition of tissue accurately captures the collaborative nature of specialized cells in biological systems.