What were some of the advancements in airplanes that made air travel affordable to the people? Name 3 of those advenments.

location is the answer to this

oil! is what i am assuming

probally   a few days after there called

aug 15, 2012 - although van leeuwenhoek was not the inventor of the microscope, he advanced it more he loved to grind and focus a new lens in order to see the unseen world. most of leeuwenhoek's microscopes were silver. in a simple but significant experiment (1668), he demonstrated that worms found on