Lets begin our tour of scientific knowledge
At the top of the heap is Cosmology. It is the sudy of the cosmos / Universe.
Cosmology is the human's attempt to understand how the universe and how our existance came about. A lot of the information is based on limited data and our limitations of understanding space and time as consept. But the human mind need to have an answer and so it does. we have many models and theories that tries to explain in human terms how it all came about.
The next level of knowledge is based what humans believe exist in the universe. Humans devised the living and non living matter.
The definition of life is based on what we define as life. So death will be opossite to life and is defined as that function that is called life is terminated and does not fnction in the same way.
Non living matter is therefore defined as matter that does not behave as living matter. Really simple .
The study of all non living matter is called physics and the study of living matter as humans definite it is called biology.