The cells is the smallest functional and structural unit of all organisms.

This is true.  A cell is the smallest unit of living matter, the basic unit of life. In multicellular organisms such as man, cells make up every tissue, organ, and organ system in the body. Man is organized in cells, tissues, organs and organ systems.

Cells  work  together in groups known as tissues. A tissue, be it plant or animal tissue,  is defined as a group of similar cells working together to carry out a certain task.

Tissues in turn are grouped together to form organs and organs are organized to into organ systems to carry out specific functions in the body.

All these is possible because of the cell, the very basic unit from which all living matter is made.

pretend they are in there underwear and you wont look at them.