Why do tissues team up to form organs

For specialization and increased efficiency

Explanation:

There are different levels of organizations of organism's body:

The cell is the basic unit of living organisms. The simplest living organisms are made up of one cell each (unicellular). Complex organisms are made up of several cells which are organized into tissues, organs and or systems depending on the level of complexity.

A group of cells performing similar functions come together to form a tissue. Group of tissues performing similar functions also come together to form organs while functionally similar organs also merge to form organ systems.

The merging of cells to form tissues, tissues to form organs and organs to form systems results in division of labour which tends to increase the efficiency of the biological processes in living organisms.

Hence, tissues team up to form organs in order to specialize and increase functional efficiency.