Definition of Physical Barriers. Physical barrier is the environmental and natural condition that act as a barrier in communication in sending message from sender to receiver. Organizational environment or interior workspace design problems, technological problems and noise are the parts of physical barriers.
Nitrate: Health Effects in Drinking Water. Nitrate is one of the most common groundwater contaminants in rural areas. It is regulated in drinking water primarily because excess levels can cause methemoglobinemia, or blue baby disease.
The worst negative effect of the Columbian exchange was the disease which brought to the people of New World such as smallpox, measles, chicken pox, malaria, influenza, cholera and many others. Syphilis disease also passed to the Europeans.