E. Muscle Any or all of these layers just described may be involved in infections. 3. DEFENSES OF SKIN AND SOFT TISSUE (review Host Defense Against Bacterial Pathogens: Defenses of Body Surfaces, pp.7-8.) A. Skin is an important anatomic barrier â bacteria and viruses cannot penetrate intact skin.
Others work closely with environmental and other scientists to preserve and clean up the environment. Geoscientists usually study and work in one of several closely related fields of geoscience. Geologists study the composition, processes, and history of the Earth.
1 Ecology â the study of the interactions of living organisms with one another and with the non-living elements of their environment. 2  Environmental biology â the study of the natural world, as a whole or in a particular area, especially as affected by human activity.