What is the term for a group of similar cells that perform specific functions?

The correct answer is 'tissues' because tissues are defined as groups of similar cells that come together to perform specific functions in the body. In biology, there are four main types of tissues: epithelial, connective, muscle, and nervous, each serving distinct roles that contribute to the overall functioning of organs and systems within an organism.

While 'organs' refer to structures made up of different types of tissues working together to perform a particular function, and 'systems' are composed of various organs that collaborate to achieve broader biological functions, neither of these terms captures the essence of a group of similar cells. 'Cells' are the basic building blocks of life, but they do not represent a group or collective, which is why 'tissues' is the most accurate term in this context.