The Most Useful (or Important) Scientific Invention

The microscope is considered one of the most useful and important scientific inventions known to 'man'.
The microscope was invented by Anton van Leeuwenhoek during the seventeenth century. Leeuwenhoek was not a scientist by profession. Initally he made a living selling clothes and buttons, but spent his spare time grinding lenses and constructing microscopes of remarkable quality, such as the light microscope. The light microscope could magnify cells, for instance in plants so you could see a clearer and bigger picture of what they are made of.
…