the biosphere
The portion of the atmosphere from sea-level to about 4000 meters in which it is possible to breathe without technological assistance.
The study of all natural phenomena: botany, zoology, mineralogy, etc.
A treatise or similar work that summarizes the known facts of either of the above.
The progression of a medical condition in an individual.
The study of all living things, especially their origins, evolution and interrelationships.