Which discovery is credited to Antony van Leeuwenhoek in the 1670s?

1. Antony van Leeuwenhoek was a Dutch shopkeeper with great skill in crafting lenses. 2. With those lenses he first observed the movements of protista and sperm, which he called animalcules. 3. In the 1670s he went on to discover bacteria and protozoa. 4. Organelles such as chloroplasts, ribosomes and lysosomes needed far later advances in lenses and staining, so they cannot be his. 5. His 1670s discovery was of bacteria and protozoa. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 4 "Cell Structure", section 4.1 Studying Cells_