The answer is bacteria. Red blood cells, Protozoa, and algae were discovered at a later time in history. He called bacteria "animalcules" because they moved and reproduced under the microscope (sort of like little animals).
Hey Brainly Student! Your answer is Bacteria or Germs. Hope this helped you!!
The chosen option is B: All of the above. Antonie van Leeuwenhoek discovered bacteria, red blood cells, and various microscopic organisms such as protozoa and algae through his early microscope in the 17th century. His pioneering work significantly contributed to the understanding of microscopic life.
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