Question

i have to write a "letter" to anton van Leeuwenhoek. i have to write a letter about the impact of the microscope on biology after the 18th century. ii need like suggestions and what to put in the letter.

Answer 1

Well, if you are writing him, you ought to know he did not invent the microscope, not even close. This is a myth that teacher seem to keep active.
Leeuwenhoek was inspired looking at some of Robert Hookes drawings from Hookes' book of microscope observations.

The impact of the microscope is that we have discovered what is inside the cell, and have learned its chemistry. With scanning electron microscopes, we have learned the structure of matter.

http://www.ucmp.berkeley.edu/history/leeuwenhoek.html