Here's a breakdown:

* Cells are the basic building blocks of life.

* Tissues are groups of similar cells that work together to perform a specific function. For example, muscle tissue is made of muscle cells that contract to allow movement.

* Organs are structures made of different tissues that work together to perform a more complex function. For instance, the stomach is an organ made of muscle tissue (for churning food), epithelial tissue (lining the stomach), and connective tissue (holding everything together).

* Organ systems are groups of organs that work together to carry out major bodily functions.

So, tissues are like the bricks that build the walls of a house, and those walls form the rooms (organs) that make up the entire house (the body).