Medical technology to treat allowed europeans to more successfully colonize tropical areas during the 1800s. a. bubonic plague b. scarlet fever c. smallpox d. malaria

The correct answer is d. Medical technology was used to treat malaria. Malaria was rampant in the tropical regions and the Europeans conquering these regions had challenges combating the disease.  The colonists and locals had a form of treatment before identifying the cause of the disease. The isolated and used quinine to treat the illness. 

The coast of north america , basically yes newfoundland , i would say c , good luck