The europeans brought infectuous diseses such as the bubonic plague, chicken pox, pneumonic plague, cholera, diphtheria, influenza, measles, scarlet fever, smallpox, typhus, tuberculosis, and whooping cough. The diseases introduced in the Americas by the Europeans were crowd diseases: that is, individuals who have once contracted the disease and survived become immune to the disease.
Answer:
The widening channel of a river where it meets the sea, mixing fresh water and salt water
The appropriate response is Continuous reinforcement. At the point when a life form gets a reinforcer each time it shows a conduct. In halfway support, additionally alluded to as irregular fortification, the individual or creature does not get strengthened each time they play out the coveted conduct.