Answer :

khadijasamreen
cell:a group of micro oraganisms known as cell
cell is the basic unit of life
tissue:a group of cells known as tissue
organ;a group of  tissue known as organ
organ system:organism  r of 2types they r multicellular and unicellular
multi means number of and uni means single
example for multi cellular organism cockroach;lizard etc
and unicellular is amoeba,paramoecium etc......
they r depeded on each other
Cell ; Cell is a basic structural and functional unit of all living organisms.
Tissues ; tissue is a group of cells that performs a specific function.
Organ ; Organ is a group of tissues that performs a specific function.
Organ system ; An organ system is a group of organs that work together to                                 perform one or more functions.
Organism ; An individual form of life that is capable of growing, metabolizing                            nutrients and reproduction is called an organism.