Science is the systematic study of anything in the Universe. In order to study nature, the early philosophers split science into manageable study groups. The main divisions are: Natural Sciences - Physical Sciences: Physics, chemistry, earth sciences, astronomy (non-living objects)
Life Sciences OR Biological Sciences: Biology, zoology, botany, (living objects). By definition it includes all
Now with multidisciplinary subjects science is fragmented further into sub specialties like Biochemistry, Cell Biology etc
"Scientific Method". Early scientists studied natural phenomena systematically through observation. This was deemed as scientific method. But as centuries passed the definitions and characteristics of the scientific methods changed. Stanford Encyclopedia of Philosophy
Characteristics of the scientific method:
Figure: The Steps in the Scientific Method.