1 Hepatitis A, B, and C are the most common viral forms of hepatitis and are the primary focus of this report. 2  Hepatitis D and E are less common hepatitis viruses. 3  Hepatitis D is a serious form of hepatitis that can be chronic. 4  It is associated with hepatitis B because the D virus relies on the B virus to replicate.
Hydrology is the study of water. Water is one of our most important natural resources. Without it, there would be no life on earth. The supply of water available for our use is limited by nature. Although there is plenty of water on earth, it is not always in the right place, at the right time and of the right quality.
The definition of astrology is the study of how the position and path of the sun, moon, and stars have a bearing on our lives. 1  A horoscope based on where celestial bodies were on the day you were born is an example of astrology. 2  The process that Egyptian rulers used to predict the future and to guide their decisions is an example of astrology.