What is a tissue made up of?

A tissue is fundamentally a group of the same type of cells that work together to perform a specific function. This is essential in the study of biology because understanding how tissues are organized helps to grasp how they contribute to the larger structures of organs and systems in the body. For example, muscle tissue is composed of muscle cells that coordinate to enable movement. Similarly, epithelial tissue comprises cells that line surfaces and cavities, demonstrating how this grouping enhances functionality.

While the other options mention different components such as various types of cells or combinations of organs, those descriptions do not accurately define what a tissue is. Tissues are characterized by their uniformity in cell type and the specific roles those cells play in maintaining the body's overall function.