Which feature of the microscope did Anton van Leeuwenhoek add that enabled him to magnify organisms about 250 times?

Leeuwenhoek’s microscopes used carefully polished, very small lenses to magnify tiny organisms. A single high-quality lens could magnify objects about 250 times. A drop of water and an oil lamp were not the feature responsible for that magnification.

AI-written and checked against the verified answer.