A person is an organism

 A person has an organ system like reproductive system and others, organ systems contains of organs working together to perform severaly closely related functions like the stomach. This organ is then made up of two or more tissues like nervous tissue which are working together to perform particular functions.

Tissues are then made up of similar cells like red blood cells working together to perform particular functions too. This Cells are then made up of organelle which are highly specialized structures like cell surface membrane. 

Organelle are then made up of macro molecules which are very large molecules important to biological processes.  Macro molecules are made up of molecules that are held together by attractive forces. This molecules are then made up of atoms which are the basic particles of the chemical elements.  

Particulary an organism be it a person, plant or animal has an organ system which helps it function.  This organ system has soo many components which helps it function properly, beginning with an atom and ends with an organ.