Question

which biologist first discovered single - celled, animalcules?
a anton van leeuwenhoek
b rudolf virchow
c mathias schleiden
d robert hooke

Explanation:

Anton van Leeuwenhoek was the first to observe and describe single - celled organisms (animalcules) using his self - made microscopes. Rudolf Virchow is known for the cell theory statement "omnis cellula e cellula". Mathias Schleiden contributed to the cell theory regarding plants. Robert Hooke is famous for coining the term "cell".

Answer:

A. Anton van Leeuwenhoek