Question

one working model- Few suggestions are as follows:

Working Model of Respiration in human.

Working Model of heart.

Working Model of Dialysis.

Working Model of Nervous system.

Working Model of Reflex action.

Working Model of Endocrine system.

Working Model of Digestive system.

Or any other Working Model of your choice (Biology).

WITH VEDIO AND EASY TO MAKE AND BEST

Answer 1

U can try  a working model of a dialyzing machine

Answer 2

In my project I've done nervous system and heart so u should do any one of this 
This are very useful and interesting as well as there r many things to know in this topics.