You don't need to make it!! If you want an easy way out just search for free 3d models online. There are some great websites out there. Like 3D Models for Professionals or Royalty free 3D models in various formats | ghantee.com. read more
Then paint it using either acrylic or poster colours. This kind of model will be lighter in weight. If you use this method, make sure to do it neatly to get a perfect shape. Making such a model like that of excretory system is a bit troublesome but you will enjoy it if you like craft work. read more
Excretory System Model In this project, students make a model of the excretory system that includes the kidneys, bladder, ureters and urethra, as well as the arteries and veins that bring blood to the kidneys for cleaning. read more