Biology is the science that deals with the study of life and how living organisms work. Biologists study all forms of life, from the smallest bacterium to the mighty blue whale. Biology looks at the characteristics of life and how life changes over time.
The definitions for physics and chemistry are pretty much the same. Physics is the study of matter and energy and the relationships between them. Physics and chemistry are called the 'physical sciences'. Sometimes physics is considered to be the science of how things work.
What Is Physics?
Geology is the study of the Earth. Geologists study what the earth is made of and how it was formed. Some people consider geology to be the study of rocks and minerals... and it is, but there is much more to it than that.
While geology is the study of everything having to do with the Earth, astronomy is the study of everything else! Astronomers study planets other than earth, stars, galaxies, black holes... the whole universe.