In the chapter test of science class 8 cell-structure and function 

question 1 it is given

Robert Hooke was the first person to observe  ____ i _____  cells. He observed these cells using a  ____ ii ______ .

I gave the answer 

i	ii
cork	magnifying glass

but they gave it wrong saying

Robert Hooke was the first person to observe cells. He observed the cells of thin slices of cork using a microscope.

The correct answer is A.

 

In the textbook pg 90 they have given that 

 

robert hooke observed slices of cork under a simple magnifying device.

 

then why my answer is given wrong